1,435 research outputs found

    Compliant and flexible business processes with business rules.

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    When modeling business processes, we often implicitly think of internal business policies and external regulations. Yet to date, little attention is paid to avoid hard-coding policies and regulations directly in control-flow based process models. The standpoint of this analysis is the role of business rule modeling in achieving business process flexibility. In particular, it is argued that flexible business process models require business rules as a declarative formalism to capture the semantics of policy and regulation. Four kinds of business rules can be used as a starting point to generate less complex control-flow-based business process models. It is shown that these different kinds of business rules relate to different perspectives in the taxonomy of business process flexibility.

    The Determination of induction and differentiation in grape vines

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    The induction and differentiation of 8-year-old Alphonse Lavallee and Sultana grape vines were studied.Defoliation methods enabled us to determine the induction time in grape vines as in other fruit species.Induction and differentiation in the tested varieties were not connected with temporary growth cessation; on the contrary, process took place during the most intensive growth.A correlation was found between the number of leaves and induction period. 18-21 leaves above the examined buds were needed in bot-h varieties to complete the induction.The leaf area needed for induction in a bud of Sultana was lYe times larger than that needed for Alphonse. The efficiency of the leaves of Alphonse to induce differentiation was thus greater.The primordia ,development from induction to detection under the microscope (differentiation) was connected with a constant vegetative development. The time needed for this development was determined by the growth rate of the variety (18 days in Sultana, 14 days in Alphonse).The translocation of materials inducing differentiation from the base of the shoot upwar,ds has not been proved in our work.In Alphonse a lag period of two days was found for the differentiation of each bud along the cane

    Tight hardness of the non-commutative Grothendieck problem

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    We prove that for any ε>0\varepsilon > 0 it is NP-hard to approximate the non-commutative Grothendieck problem to within a factor 1/2+ε1/2 + \varepsilon, which matches the approximation ratio of the algorithm of Naor, Regev, and Vidick (STOC'13). Our proof uses an embedding of 2\ell_2 into the space of matrices endowed with the trace norm with the property that the image of standard basis vectors is longer than that of unit vectors with no large coordinates

    Tight hardness of the non-commutative Grothendieck problem

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    We prove that for any ε > 0 it is NP-hard to approximate the non-commutative Grothendieck problem to within a factor 1=2+ε, which matches the approximation ratio of the algorithm of Naor, Regev, and Vidick (STOC’13). Our proof uses an embedding of ℓ2 into the space of matrices endowed with the trace norm with the property that the image of standard basis vectors is longer than that of unit vectors with no large coordinates. We also observe that one can obtain a tight NP-hardness result for the commutative Little Grothendieck problem; previously, this was only known based on the Unique Games Conjecture (Khot and Naor, Mathematika 2009)

    Process algebra modelling styles for biomolecular processes

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    We investigate how biomolecular processes are modelled in process algebras, focussing on chemical reactions. We consider various modelling styles and how design decisions made in the definition of the process algebra have an impact on how a modelling style can be applied. Our goal is to highlight the often implicit choices that modellers make in choosing a formalism, and illustrate, through the use of examples, how this can affect expressability as well as the type and complexity of the analysis that can be performed

    Mapping Specific Mental Content during Musical Imagery

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    Humans can mentally represent auditory information without an external stimulus, but the specificity of these internal representations remains unclear. Here, we asked how similar the temporally unfolding neural representations of imagined music are compared to those during the original perceived experience. We also tested whether rhythmic motion can influence the neural representation of music during imagery as during perception. Participants first memorized six 1-min-long instrumental musical pieces with high accuracy. Functional MRI data were collected during: 1) silent imagery of melodies to the beat of a visual metronome; 2) same but while tapping to the beat; and 3) passive listening. During imagery, inter-subject correlation analysis showed that melody-specific temporal response patterns were reinstated in right associative auditory cortices. When tapping accompanied imagery, the melody-specific neural patterns were reinstated in more extensive temporal-lobe regions bilaterally. These results indicate that the specific contents of conscious experience are encoded similarly during imagery and perception in the dynamic activity of auditory cortices. Furthermore, rhythmic motion can enhance the reinstatement of neural patterns associated with the experience of complex sounds, in keeping with models of motor to sensory influences in auditory processing

    Chosen-ciphertext security from subset sum

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    We construct a public-key encryption (PKE) scheme whose security is polynomial-time equivalent to the hardness of the Subset Sum problem. Our scheme achieves the standard notion of indistinguishability against chosen-ciphertext attacks (IND-CCA) and can be used to encrypt messages of arbitrary polynomial length, improving upon a previous construction by Lyubashevsky, Palacio, and Segev (TCC 2010) which achieved only the weaker notion of semantic security (IND-CPA) and whose concrete security decreases with the length of the message being encrypted. At the core of our construction is a trapdoor technique which originates in the work of Micciancio and Peikert (Eurocrypt 2012

    Impact assessment of the biological control of the cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae), by the introduced parasitoid Epidinocarsis lopezi (De Santis) (Hymenoptera: Encyrtidae)

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    The impact of Phenacoccus manihoti Matile-Ferrero on growth and tuber yield of cassava, and the results of its biological control by the exotic parasitoid Epidinocarsis lopezi (De Santis) were investigated in a survey of 60 farmers' fields in Ghana and Ivory Coast over an area of 180 000 km2 of the savana and forest ecosystems. Twenty-nine variables associated with plant growth, agronomic and environmental factors, and insect populations were recorded. Densities of P. manihoti were closely correlated with stunting of the cassava shoot tips and, less so, with the rate of stunting early in the growing season. With increasing mealybug infestations, average harvest indices declined and populations of E. lopezi and of indigenous coccinellids increased, but parasitoids were found at lower host levels than were predators. The length of time E. lopezi had been present in an area was the most important factor influencing mealybug densities. Thus, P. manihoti populations were significantly lower where E. lopezi had been present for more than half the planting season than in areas where E. lopezi was lacking or had been only recently introduced. A significant proportion of the farmers in the savanna zone, where P. manihoti populations were much higher than in the forest zone, had observed this decline due to E. lopezi. Tuber yield losses due to P. manihoti in the absence of E. lopezi were tentatively estimated at 463 g/plant in the savanna zone. No significant effect was found in the forest region. When E. lopezi was present, average P. manihoti damage scores were reduced significantly, both in the savanna and forest regions. The increase in yields was 228g/plant or about 2.48 t/ha in the savanna regio

    Diamagnetic Blob Interaction Model of T Tauri Variability

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    Assuming a diamagnetic interaction between a stellar-spot originated localized magnetic field and gas blobs in the accretion disk around a T- Tauri star, we show the possibility of ejection of such blobs out of the disk plane. Choosing the interaction radius and the magnetic field parameters in a suitable way gives rise to closed orbits for the ejected blobs. A stream of matter composed of such blobs, ejected on one side of the disk and impacting on the other, can form a hot spot at a fixed position on the disk (in the frame rotating with the star). Such a hot spot, spread somewhat by disk shear before cooling, may be responsible in some cases for the lightcurve variations observed in various T-Tauri stars over the years. An eclipse-based mechanism due to stellar obscuration of the spot is proposed. Assuming high disk inclination angles it is able to explain many of the puzzling properties of these variations. By varying the field parameters and blob initial conditions we obtain variations in the apparent angular velocity of the hot spot, producing a constantly changing period or intermittent periodicity disappearance in the models.Comment: 6 pages, 4 figures, aas2pp4 styl
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