Kinds Of Constraints Research Articles

A simple and quick control strategy for a class of first-order nonholonomic manipulator

This paper presents a simple and quick control strategy for a class of first-order nonholonomic manipulator: planar n-link manipulator with a passive first joint (no gravity). The control target is driving its endpoint from any initial position to any target position. First, we reduce the planar n-link manipulator to a planar three-link one by maintaining the states (angles and angular velocities) of n-3 active links in the initial value all the time. That is, we only adjust the states of the remaining two active links in the whole control process, and these two adjusted active links are chosen to guarantee that the target position is in the reachable region of the planar n-link manipulator by using the enumeration method. Then, we divide the whole control process into two stages for the reduced planar three-link manipulator. In each stage, the manipulator becomes a planar two-link one by maintaining the states of one adjusted active link to be the constant value. The state constraint existing between the passive first link and the adjusted active link is obtained by using the integral characteristics of a planar two-link manipulator. Meantime, the geometric constraint between the position of the endpoint and angles of all joints is obtained based on the homogeneous coordinate transformation method. According to the above two kinds of constraint, the target angles of the two adjusted active links are calculated by employing the particle swarm optimization algorithm. When the two adjusted active links are controlled to their target angles in turn, the control target of the planar n-link manipulator is completed. Finally, simulation results demonstrate that the proposed control strategy is valid and rapid.

U.S. States’ fiscal constraints and effects on budget policies

Abstract The article looks at fiscal constraints adopted by the U.S. States. It questions the ability of those rules to determine sound budgetary policies. To assess this point it analyses, in the general part, the major kind of constraints so far adopted. Of each major category the focus is upon institutional weaknesses that create the room for the adoption of circumventing practices. The following section focuses instead on three case studies, to show examples of the way in which the constraints influenced policy-making without mining the ability of government to adopt unbalanced budgetary policies. The weaknesses are combined with the adoption of a deferential approach by the Courts that generally legitimized the accounting devices adopted by the States. The outcome is a system in which budget policies are influenced by several factors that go beyond the institutional framework. On the other side, legal boundaries create distortions and unwanted effects in policies implemented by the States.

Form Has Its Reasons: Translation and Copia

Form Has Its Reasons: Translation and Copia Rachel Galvin (bio) The Oulipo has always had a special relationship to translation. A form of translation is embedded in its fundaments, as Oulipians seek to translate elements from the sphere of mathematics into potential literary structures. Raymond Queneau investigated the permutative potential of translation in his Exercises in Style, which tells the same brief, banal tale in ninety-nine distinct fashions. Modeled on a progymnysmata, or handbook of classical rhetoric, the book resembles a translators’ guide to modulating form, from the most subtle to the most radical of phonetic, lexical, syntactical, and tonal gradations. Queneau’s book illustrates Jorge Luis Borges’ assertion that an original, just like its multiple translations, are all simply drafts, and that “Presuponer que toda recombinación de elementos es obligatoriamente inferior a su original, es presuponer que el borrador 9 es obligatoriamente inferior al borrador H—ya que no puede haber sino borradores. El concepto de texto definitivo no corresponde sino a la religión o al cansancio” (“To assume that every recombination of elements is necessarily inferior to its original form is to assume that draft 9 is necessarily inferior to draft H—for there can only be drafts. The concept of the ‘definitive text’ corresponds only to religion or exhaustion”; Borges 69). Exercices de style is composed solely of drafts, with no definitive version of the narrative.2 [End Page 846] We might also say that translation is fundamentally more Oulipian than has been recognized. Borges helps us see that translation is a form of literary production rather than reproduction. This is particularly palpable in the case of constrained literature, since translating constrained texts requires not only following the original constraint to produce a new text in a different language, but also applying the constraints of translation to the preexisting text. Multilingual Oulipians regularly engage in this process. Hervé Le Tellier has made the remarkable declaration that “toute traduction d’une œuvre oulipienne est un exploit et une œuvre oulipienne en soi” (Le Tellier 247). This fascinating claim is worth lingering over, for it proposes a rather radical philosophy of composition. Le Tellier munificently suggests that constrained translation should be honored as an act of origination. The translator is symbolically absorbed back into the very collective she is attempting to ferry across into another linguistic space. The Oulipo thus gathers its translators under its ample skirts, in a conceptual move similar to that of anticipatory plagiarism (plagiat par anticipation). Not only do Oulipians look back to authors who lived long before the Oulipo was founded and name them anticipatory plagiarists of Oulipian methods, but they also look forward to future translators and proleptically adopt them into the Oulipian endeavor. We may detect a potentially aggressive note in this adoption. It allows the Oulipo to spread out, like the Borg, and assimilate its translators into the collective. (Which raises the question: does the translator need to bite back against this subsumption?) Le Tellier’s idea also reconfigures translation, à la Borges, as a draft equal in stature to the original. Primacy loses its meaning and the metaphysics of origin is drained of its power. (By “metaphysics of origin” I refer to the theology of “the new, the creative, the true” that leads to myths about literary originality [Meltzer 6]). The more we examine it, the more radical a theory of translation Le Tellier’s assertion shows itself to be. The claims I make in this essay are pitted against ideas of fidelity and originality. There is no original text to which one must be faithful, as Borges affirmed. I will be arguing that Oulipian constraints often resemble translation techniques; that translation itself is a kind of constraint; and that both entail copia in Jacques Roubaud’s sense (a concept I will detail in a moment). There is a manifest family resemblance between the treatment Roubaud gives Queneau in riffing on him, the translated constrained texts such as A Void, Gilbert Adair’s version of Georges Perec’s La Disparition, and the dizzying number of Oulipian versions, responses, or translations of Perec’s Voyage d’hiver, [End Page 847] for example.3 Since I am grouping texts infrequently...

Beautification and efficiency improvement of 3D modelling with the help of geometric constraints

We emphasise on the influence of geometric constraints in 3D reconstruction. In fact, we have used a new approach of 3D reconstruction which is based on bundle adjustment optimisation and constraints. Our purpose is to achieve 3D reconstruction in a simple, fast and efficient way without any prior information about cameras and 3D space. Constraints use brings us many advantages; it helps us to reduce estimated parameters number and stabilises good results quality. We try as much as possible through a comparative analysis to prove the importance of constraints use, in terms of results reliability, process speed and convergence rate. We use uncalibrated views, so we don't have any pertinent initial values used in Levenberg-Marquardt. On the hand, and thanks to the estimation of cameras' positions with constraints during Levenberg-Marquardt optimisation, we solve with the convergence problem satisfactorily. Several data will be used with the aim to demonstrate the efficiency of our present approach under different uses and kinds of constraints.

Application of Three Meta-Heuristic Algorithms for Maximizing the Net Present Value of a Resource-Constrained Project Scheduling Problem with Respect to Delay Penalties

The Resource Constrained Project Scheduling Problem (RCPSP) is been studied under different kinds of constraints and limitations. In this paper, we are going to consider the discounted cash flows for project activities, and delay penalties which occur when the project make span exceeds its deadline as the objective function of the RCPSP. To solve the model, we will take advantage of three different meta-heuristic algorithms - Genetic Algorithm (GA), Imperialist Competitive Algorithm (ICA), and Shuffled Frog Leaping Algorithm (SFLA) - to achieve the optimal solution of the problem. The evaluation of the algorithms performance reveals that, in comparison with ICA and SFLA, GA performs better, especially in large-scale problems.

The Spatial-Temporal Distribution of the Coupling between Urbanization and Farmland Resources in the Mainland of China

An evaluation index system was constructed for the coupling between urbanization and farmland resources, based on data from 31 provinces in the mainland of China. Using the Grey Relational Analysis method, the spatial-temporal variations of the coupling between them can be revealed. The conclusions of this study were: (1) the stress of urbanization on farmland resources is dominated by economic urbanization, while this kind of constraint also produces the strongest influence on the status (endowment) of the arable resources; (2) viewed over time, the coupling degree in Chinese provinces between urbanization and farmland resources shows volatility and internal differences: East > West > Central regions, and the causes for these differences are also discussed; (3) The interaction between them is spatially strong, and the coupling degree is relatively close and high, showing the coexisting features of complexity and specificity. Combining the coupling with the urban level the 31 provinces can be categorized into four types: Low-level Coupled Mode, Antagonism Mode, Transition Mode and Coordination Mode.

Beautification and efficiency improvement of 3D modelling with the help of geometric constraints

We emphasise on the influence of geometric constraints in 3D reconstruction. In fact, we have used a new approach of 3D reconstruction which is based on bundle adjustment optimisation and constraints. Our purpose is to achieve 3D reconstruction in a simple, fast and efficient way without any prior information about cameras and 3D space. Constraints use brings us many advantages; it helps us to reduce estimated parameters number and stabilises good results quality. We try as much as possible through a comparative analysis to prove the importance of constraints use, in terms of results reliability, process speed and convergence rate. We use uncalibrated views, so we don't have any pertinent initial values used in Levenberg-Marquardt. On the hand, and thanks to the estimation of cameras' positions with constraints during Levenberg-Marquardt optimisation, we solve with the convergence problem satisfactorily. Several data will be used with the aim to demonstrate the efficiency of our present approach under different uses and kinds of constraints.

Cuckoo optimization algorithm with penalty function for combined heat and power economic dispatch problem

The CHPED (combined heat and power economic dispatch) is a complex engineering optimization problem. The goal is to minimize the system production costs by taking into consideration different kind of constraints. This research investigates the first implementation of a prevailing bio-inspired metaheuristic called the cuckoo optimization algorithm which is powered by a penalty function (PFCOA) for solving the CHPED problem. Two case studies of the CHPED are presented and the results are compared to those obtained by several other optimization techniques applied in the literature. It has been proven that the implemented PFCOA is superior.

The Spatiality of Cognition in the Zhuangzi

In this paper I explore the conception of cognition and action found in the Inner Chapters of the Zhuangzi . More specifically, I focus on the role of explicit and implicit spatial imagery in the context of this complex problem. Spatial imagery suggests that cognition is understood as fundamentally bimodal in the text: (1) the default modality, which is informed by an entrenched distinction pattern, is cast in terms of fullness and bulk; and (2) the auxiliary modality, which is free from this kind of constraint, is imagined in terms of emptiness and lack of bulk, as an axis or point. The latter is the preferred mode of engagement with the environment, according to the Zhuangzi . Spatial imagery brings out the crucial characteristics of this cognitive modality: its radical openness and infinite fecundity in the context of distinction–drawing and action. It also connects with other metaphorical schemata at work in the text, including organic imagery. Interestingly, the notion of emptiness and the figure of an axis do not mark an experience of undifferentiated oneness but the state of heightened sensitivity to the makeup of one’s environment. Such sensitivity allows the agent to entertain the situation at hand without bias and to move around (relatively) conflict–free.

Research on the optimization approach for cargo oil tank design based on the improved particle swarm optimization algorithm

Based on the improved particle swarm optimization (PSO) algorithm, an optimization approach for the cargo oil tank design (COTD) is presented in this paper. The purpose is to design an optimal overall dimension of the cargo oil tank (COT) under various kinds of constraints in the preliminary design stage. A non-linear programming model is built to simulate the optimization design, in which the requirements and rules for COTD are used as the constraints. Considering the distance between the inner shell and hull, a fuzzy constraint is used to express the feasibility degree of the double-hull configuration. In terms of the characteristic of COTD, the PSO algorithm is improved to solve this problem. A bivariate extremum strategy is presented to deal with the fuzzy constraint, by which the maximum and minimum cargo capacities are obtained simultaneously. Finally, the simulation demonstrates the feasibility and effectiveness of the proposed approach.

Power to the people: freedom as non-domination, disabling constraints and the eyeball test

While there has been a large focus on what it means to be unfree in the neo-Roman republican literature, what it means to be non-free has received much less attention. Prima facie, this should not be surprising. After all, we tend to hold a special place in our normative theorising for the kinds of constraints that come about via the intentional actions of other agents rather than those that come about via the indirect, aggregate action of independently motivated social actors. However, as I argue in this article, if republicans advocate ‘structural egalitarianism’ as Pettit claims, then there are certain disabling constraints – constraints derived solely from being non-free in a choice – that deserve closer attention. Indeed, I claim that in failing to fully appreciate the importance of non-freedom, Pettit’s ‘eyeball test’ – the yardstick for republican justice – leaves in place certain disabling constraints to action which render some citizens structurally unequal vis-à-vis others.

Republicanism: Religious Studies and Church History meet Political History

Republicanism, both of these authors teach us, by the mid-nineteenth century became indistinguishable from the aims of religion in the United States. A broad array of protestants agreed that the aims of religion cohered with the political principle of republicanism—or the principle that men could only achieve freedom through self-rule. Noll usefully shows that this concept of republicanism underwent a series of changes from the late eighteenth century to the mid-nineteenth. Beginning in the late eighteenth century republicanism referenced liberty from tyranny, man as citizen, and virtue as a kind of constraint on individual interests. Noll, however, argues that two versions of republicanism competed in this earlier period: communitarian republicanism, based in “the reciprocity of personal morality and social-well being,” and liberal republicanism, which valued the independence of the individual. Noll and Modern argue that by the mid-nineteenth century, the liberal version won out. Citizens imagined their freedom to be enabled by a market-based society more than by a community of virtue. For political historians these definitions are not new or controversial, but for historians of American religious history republicanism is an unlikely category of analysis because we see it as “political theory” rather than theology. But as both Noll and Modern argue, republicanism became the very substance of theology in the United States.

Joint Scheduling of Large-Scale Appliances and Batteries Via Distributed Mixed Optimization

This paper investigates joint scheduling problem of large-scale smart appliances and batteries (e.g., in a smart building), to minimize electricity payment, user's dissatisfaction and battery loss under kinds of constraints. Due to the binary nature of charge and discharge states of battery, this problem is formulated as a constrained mixed-integer nonlinear program. In order to solve it efficiently, a distributed mixed optimization approach is proposed. First, Lagrangian relaxation is applied to decompose the original problem into two sets of subproblems, each of which corresponds to scheduling on appliance/battery. Then, the battery scheduling subproblem is formulated as a mixed-integer linear program and tackled by Benders decomposition. The main advantages of the proposed approach are the distributed implementation and low computational complexity, as shown by simulations.

Interactive constrained dynamics for rigid and deformable objects

AbstractFollowing the continuous increase in computational power of consumer hardware, interactive virtual environments have been recently enriched with more and more complex deformable objects. However, many physics engines are still very limited in the way they handle interacting rigid and deformable objects. This paper proposes a constraint‐based approach to real‐time simulation of coupled rigid and deformable objects capable of providing two‐way interactions. Similar techniques have seen widespread usage for either rigid or deformable objects, but not for the simultaneous simulation of both. By extending such approaches, we show not only how interaction is possible but also how it can be performed at real‐time rates. We address contact response and also show how to implement typical constraints to enforce limitations in the degrees of freedom and to enhance the dynamical properties of deformable objects. The method is easily integrated into existing physics engines that use similar constraint solvers and is independent on the kind of deformable object paradigm chosen. The provided simulation results show that the method is fast and effective in handling contacts between rigid and deformable objects and in simulating friction and other kinds of constraints. Copyright © 2015 John Wiley & Sons, Ltd.

Constrained clustering by constraint programming

Constrained Clustering allows to make the clustering task more accurate by integrating user constraints, which can be instance-level or cluster-level constraints. Few works consider the integration of different kinds of constraints, they are usually based on declarative frameworks and they are often exact methods, which either enumerate all the solutions satisfying the user constraints, or find a global optimum when an optimization criterion is specified. In a previous work, we have proposed a model for Constrained Clustering based on a Constraint Programming framework. It is declarative, allowing a user to integrate user constraints and to choose an optimization criterion among several ones. In this article we present a new and substantially improved model for Constrained Clustering, still based on a Constraint Programming framework. It differs from our earlier model in the way partitions are represented by means of variables and constraints. It is also more flexible since the number of clusters does not need to be set beforehand; only a lower and an upper bound on the number of clusters have to be provided. In order to make the model-based approach more efficient, we propose new global optimization constraints with dedicated filtering algorithms. We show that such a framework can easily be embedded in a more general process and we illustrate this on the problem of finding the optimal Pareto front of a bi-criterion constrained clustering task. We compare our approach with existing exact approaches, based either on a branch-and-bound approach or on graph coloring on twelve datasets. Experiments show that the model outperforms exact approaches in most cases.

A co-evolutionary improved multi-ant colony optimization for ship multiple and branch pipe route design

This paper presents a co-evolutionary improved multi-ant colony optimization (CIMACO) algorithm for ship multi and branch pipe route design. The purpose of CIMACO algorithm is to design appropriate pipe routes to connect the starting points and ending points in the layout space under various kinds of constraints. The ant colony optimization (ACO) algorithm is improved according to the characteristics of ship pipe routing which is used to solve the single pipe routing problem. Based on the improved ACO algorithm, the multi ant colony optimization (MACO) algorithm with co-evolution mechanism is used to solve the multi and branch pipe routing problem. In this paper, the pheromone direction information and pheromone extension process are developed in the proposed algorithm to improve the calculation performance. Compared with conventional method, CIMACO algorithm is better at avoiding the problem of local optimum and accelerating the convergence rate. Finally, the simulation results demonstrate the feasibility and efficiency of the proposed algorithm.

Canonical quantization of classical fields in finite volume

We study the problem of canonical quantization of classical scalar and Dirac field theories in the finite volumes respectively in this paper. Unlike previous studies, we work in a completely discrete version. We discretize both the space and time variables in variable steps and use the difference discrete variational principle with variable steps to obtain the equations of motion and boundary conditions as well as the conservation of energy in discrete form. For the case of classical scalar field, the quantization procedure is simpler since it does not contain any intrinsic constraint. We take the boundary conditions as primary Dirac constraints and use the Dirac theory to construct Dirac brackets directly. However, for the case of classical Dirac field in a finite volume, things are complex since, besides boundary conditions, it contains intrinsic constraints which are introduced by the singularity of the Lagrangian. Furthermore, these two kinds of constraints are entangled at the spatial boundaries. In order to simplify the process of calculation, we calculate the final Dirac brackets in two steps. We calculate the intermediate Dirac brackets by using intrinsic constraints. And then, we obtain the final Dirac brackets by bracketing the boundary conditions. Our studies show that we can not only construct well-defined Dirac brackets at each discrete space-time lattice but also keep the conservation of energy discretely at the same time.

PATH PLANNING FOR VISUAL SERVOING AND NAVIGATION USING CONVEX OPTIMIZATION

Exploiting visual cues to control systems for robotic applications is a promising idea. Practically, they are usable only if the end result accedes to the restrictions of the specific environment. These restrictions are like the limited field of view of the camera and physical constraints of the workspace of the robot. Hence, there is a need for a general framework that can be used adaptively across various environments. We develop such an algorithmic framework that is flexible to accommodate various kinds of constraints and generate a solution that is optimal in the sense of the considered error measure. We perform a constrained optimization on the error in a convex domain considering all the necessary constraints using convex optimization techniques and further extend it to nonconvex domains. We utilize branch-and-bound algorithm to divide the problem of optimizing over a range of rotations into simpler problems and solve for the optimal rotation. We demonstrate the performance of the algorithm by generating control signals in a simulated framework for visual servoing and in a real-world for robot

Two Sides of the Same Rupee? Comparing Demand for Microcredit and Microsaving in a Framed Field Experiment in Rural Pakistan

Following recent literature, we hypothesise that saving and borrowing among microfinance clients are substitutes, satisfying the same underlying demand for a regular deposit schedule and a lumpsum withdrawal. We test this using a framed field experiment among women participating in group lending in rural Pakistan. The experiment — inspired by the rotating structure of a ROSCA — involves randomly offering credit products and savings products to the same subject pool. We find high demand both for credit products and for savings products, with the same individuals often accepting both a credit product and a savings product over the three experiment waves. This behaviour can be rationalised by a model in which individuals prefer lump-sum payments (for example, to finance a lumpy expenditure), and in which individuals struggle to hold savings over time. We complement our experimental estimates with a structural analysis, in which different types of participants face different kinds of constraints. Our structural framework rationalises the behaviour of 75% of participants; of these ‘rationalised’ participants, we estimate that two-thirds have high demand for lump-sum payments coupled with savings difficulties. These results imply that the distinction between microlending and microsaving is illusory; participants value a mechanism for regular deposits and lump-sum payments, whether that is structured as a credit or debt contract.

Discussion

Discussion