Coordination Constraints Research Articles

Remarks on “Gapping” in DP

We argue that the gapping-like constructions in the nominal domain (nominal gapping: NG) and regular gapping constructions seen in clauses (verbal gapping: VG) show quite different properties. First, VG obeys the Coordination Constraint but NG does not. Second, in terms of locality, NG allows free embedding but VG does not. Third, the scope properties exhibited in VG are not seen in NG. Fourth, socalled cross-conjunct binding, which is sometimes taken as strong evidence for the across-the-board movement analysis of VG, is not seen in NG in the same way as in VG, even in the environments where locality requirements for across-the-board movement are met. We argue that the derivation of NG does not involve across-the-board movement. Instead, NG is best analyzed as involving ellipsis.

Optimization of the law of moving object evasion from detection under constraints

Consideration was given to optimization of the laws of moving object evasion from detection under the coordinate and phase constraints.

Developmental constraints of quadrupedal coordination across crawling styles in human infants.

Human infants can crawl using several very different styles; this diversity appears at first glance to contradict our previous findings from hands-and-knees crawling, which suggested that there were strict limitations on coordination, imposed either mechanically or by the developing nervous system. To determine whether coordination was similarly restricted across crawling styles, we studied free crawling overground in 22 infants who used a number of different locomotor strategies. Despite the wide variety in the use of individual limbs and even the number of limbs used, the duration of the stance phase increased with duration of cycle, whereas the duration of the swing phase remained more constant. Additionally, all infants showed organized, rhythmic interlimb coordination. Alternating patterns (e.g., trotlike) predominated (86% of infants). Alternatively, yet much less frequently, all limbs used could work in synchrony (14% of infants). Pacelike patterns were never observed, even in infants that crawled with the belly remaining in contact with the ground so that stability was not a factor. To explore the robustness of the interlimb coordination, a perturbation that prolonged swing of the leg was imposed on 14 additional infants crawling on hands and knees overground or on the treadmill. The perturbation led to a resetting of the crawling pattern, but never to a change in the coordination of the limbs. The findings concur with those regarding other infant animals, together suggesting that the nervous system itself limits the coordination patterns available at a young age.

A derivational ellipsis approach to ATB-movement

This article argues for an ellipsis approach to ATB-movement on the basis of morphosyntactic mismatches and reconstruction asymmetries between conjuncts. I will argue that ATB-moved constituents are present in each conjunct; while those in the first conjunct undergo asymmetric extraction, those in the sec - ond conjunct are elided under identity with those in the first. Ellipsis in ATB is licensed by means of an (E) atb-feature whose selectional restrictions correctly sin- gle out the elements that can undergo ATB-movement. Ellipsis applies deriva- tionally and makes the elided constituents inaccessible for further syntactic o perations. Asymmetric extraction is sanctioned by a representational definition of the Coordinate Structure Constraint: At LF, the asymmetrically extracted oper - ator can bind both its own trace as well as the trace left behind by the operator in the second conjunct. Binding into the second conjunct is only possible if both operators bear the same index; this in turn is guaranteed by the recoverability condition on ellipsis, which requires an identical antecedent. Since the operator can bind both variables, the single-identity reading characteristic of ATB is cor -

On the grammar of extraction and coordination

This paper examines English unbounded dependency constructions and concludes that the syntactic mechanism responsible for extraction operates in the same way in all constructions, regardless of the structures being subordinate or coordinate. In other words, this work argues that there is a general and fully uniform mechanism behind the linkage of ‘gaps’ and their ‘fillers’ in the family of constructions that allow such unbounded dependencies. Crucially, this mechanism is devoid of exceptions, and interacts with other aspects outside the grammar of extraction to predict the Coordinate Structure Constraint, ATB extractions, parasitism, and at least certain islands. Although the underlying syntactic mechanism for extraction is argued to work in the same way for all constructions, certain parts of the grammar can locally impose additional conditions on the possible extraction patterns. Along with recent psycholinguistic and neurolinguistic research, it is argued that many apparent exceptions result from independently motivated performance factors, also observed in garden-path sentences and center-embedded constructions.

Climate change implications for disaster risk management in Japan: A case study on perceptions of risk management personnel and communities in Saijo city

This paper reviews climate change impacts and the existing disaster risk management system in Japan and offers the results of a structured questionnaire survey of the community leaders and disaster risk management personnel of Saijo city of Japan that assesses their perceptions about dealing with the extreme disasters by the existing disaster risk management systems. This study was inspired by the record number of typhoon landfall that has surprised the local government and communities in 2004. While unearthing the hidden vulnerabilities in cities like Saijo, this event has loosened the confidence of local communities on the disaster risk management systems. From the study, we conclude that the existing disaster risk management systems need further fillip and that the proactive community involvement in disaster risk management is still in nascent stages. Associating with the scientific community, involving the local communities (including the elderly), enhancing the redundancy in disaster risk management systems, inculcating strategic thinking and micro-level planning, conducting vulnerability assessments by considering the special circumstances including resource constraints of small cities and better policy coordination across the administrative hierarchy are some important considerations for dealing with the uncertainty brought by the extreme events.

Iron(II) Vacataporphyrins: A Variable Annulene Conformation inside a Regular Porphyrin Frame

5,10,15,20-Tetraaryl-21-vacataporphyrin (1), an annulene-porphyrin hybrid containing a butadiene fragment in the macrocycle perimeter, gives paramagnetic iron(II) complexes 2. The porphyrin 1 is devoid of one donor atom of the coordination core; hence, metal ion is bound in the macrocyclic cavity by only three pyrrolic nitrogen atoms. The coordination sphere in 2-X (where X = Cl, Br, I) is completed by a halide anion. The butadiene fragment flexibility and constraints of coordination lead to two stereoisomers with the chain oriented inward (2-i-X) or outward (2-o-X) of the macrocyclic center. Axial halide subtraction (AgBF(4) addition) leads to two new forms differing in the butadiene chain configuration. The (1)H NMR spectra of all complexes show characteristics typical for high-spin iron(II) complexes of porphyrinoids. The dependence of the relaxation times T(1) versus Fe(II)···H distances (estimated by MM+ models) for three of the isomers is in accordance with the in, out, and/or zigzag geometries. The 2-o-X complex is more reactive than 2-i-X and reacts at room temperature with dioxygen to form the iron(II) 21-oxaporphyrin complex, conserving the iron(II) oxidation state. After the addition of imidazole or excess of methanol to a mixture of 2-o-X and 2-i-X, single five-coordinate complexes with out annulene configuration and two axial ligands are formed.

Three-dimensional path planning for unmanned aerial vehicle based on linear programming

SUMMARYIn this paper, an approach based on linear programming (LP) is proposed for path planning in three-dimensional space, in which an aerial vehicle is requested to pursue a target while avoiding static or dynamic obstacles. This problem is very meaningful for many aerial robots, such as unmanned aerial vehicles. First, the tasks of target-pursuit and obstacle-avoidance are modelled with linear constraints in relative coordination according to LP formulation. Then, two weighted cost functions, representing the optimal velocity resolution, are integrated into the final objective function. This resolution, defined to achieve the optimal velocity, deals with the optimization of a pair of orthogonal vectors. Some constraints, such as boundaries of the vehicle velocity, acceleration, sensor range, and flying height, are considered in this method. A number of simulations, under static and dynamic environments, are carried out to validate the performance of generating optimal trajectory in real time. Compared with ant colony optimization algorithm and genetic algorithm, our method has less parameters to tune and can achieve better performance in real-time application.

Testing Multiple Coordination Constraints with a Novel Bimanual Visuomotor Task

The acquisition of a new bimanual skill depends on several motor coordination constraints. To date, coordination constraints have often been tested relatively independently of one another, particularly with respect to isofrequency and multifrequency rhythms. Here, we used a new paradigm to test the interaction of multiple coordination constraints. Coordination constraints that were tested included temporal complexity, directionality, muscle grouping, and hand dominance. Twenty-two healthy young adults performed a bimanual dial rotation task that required left and right hand coordination to track a moving target on a computer monitor. Two groups were compared, either with or without four days of practice with augmented visual feedback. Four directional patterns were tested such that both hands moved either rightward (clockwise), leftward (counterclockwise), inward or outward relative to each other. Seven frequency ratios (3∶1, 2∶1, 3∶2, 1∶1, 2∶3. 1∶2, 1∶3) between the left and right hand were introduced. As expected, isofrequency patterns (1∶1) were performed more successfully than multifrequency patterns (non 1∶1). In addition, performance was more accurate when participants were required to move faster with the dominant right hand (1∶3, 1∶2 and 2∶3) than with the non-dominant left hand (3∶1, 2∶1, 3∶2). Interestingly, performance deteriorated as the relative angular velocity between the two hands increased, regardless of whether the required frequency ratio was an integer or non-integer. This contrasted with previous finger tapping research where the integer ratios generally led to less error than the non-integer ratios. We suggest that this is due to the different movement topologies that are required of each paradigm. Overall, we found that this visuomotor task was useful for testing the interaction of multiple coordination constraints as well as the release from these constraints with practice in the presence of augmented visual feedback.

Overcurrent Relays Coordination Considering the Priority of Constraints

In interconnected networks, it is impossible to satisfy all coordination constraints. Some methods have been proposed in the literature to determine the minimum break point set (MBPS) before the coordination procedure. In this paper, a new method is presented which coordinates overcurrent relays and simultaneously determines minimum unsatisfied constraints as broken constraints (BCs). For the implementation of this method, a new objective function (OF) is defined that also includes constraints with various weightings. These weightings determine the priority of constraints for being satisfied which are obtained by means of some expert rules. The expert rules of previous papers are modified and weighted to determine the priority of constraints. The genetic algorithm is used to optimize the OF that has an internal feedback for determining the minimum BCs considering coordination criterion. The effectiveness of the proposed technique is demonstrated by comparing the results of two sample networks with those obtained by using the recently developed techniques.

Constrained load/frequency control problems in networked multi-area power systems

In this paper, we present a supervisory discrete-time predictive control strategy for load/frequency control problems in networked multi-area power systems subject to coordination constraints. Coordination between the control center and the spatially distributed areas is accomplished via data networks subject to communication latency modeled by time-varying time-delay. The aim here is finding supervising strategies able to reconfigure, whenever necessary in response to unexpected load changes and/or faults, the nominal set-points on frequency and generated power to the generators of each area so that viable evolutions would arise for the overall power system and a new sustainable equilibrium is reached. In order to demonstrate the effectiveness of the strategy, examples on a four-area power system are presented.

Coordination operators and their composition under the actor-role-coordinator (ARC) model

For large open and distributed real-time applications, coordination constraints among concurrent, spatially distributed and autonomous entities can be complex. The Actor-Role-Coordinator (ARC) model we developed earlier [1] introduced the concept of roles which are abstractions of behaviors that are to be coordinated. Each role's behaviors may be shared by many concurrent entities, or played by many actors . Based on the role concept, coordination activities in large systems are partitioned into inter-role and intra-role coordinations to mitigate the coordination complexity. This paper focuses on coordination primitives and the composition of these primitives in forming more complex intra-role and inter-role coordination constraints. In particular, we define two primitive coordination operators, i.e., precede (≺ t ) and select (⊵ p ), and use them to express temporal and spacial (with respect to actor system's behavioral space) coordination constraints among concurrent and autonomous actors. We further provide an operational semantics for these operators under the ARC model and provide case studies to illustrate their expressiveness in specifying complex coordination constraints.

Distributed Reference Management Strategies for Networked Water Distribution Systems

AbstractA distributed constrained supervisory strategy for large-scale spatially distributed systems is presented and applied to a networked water distribution system. The aim is at reconfiguring, whenever necessary in response to different supply downstream demands, the nominal set-points to the tank water levels so that all prescribed coordination and operational constraints are enforced during the system evolutions and sustainable equilibria are reached. The presented supervision strategy follows a coordination-by-constraint approach and is based on Feed-Forward Command Governor (FF-CG) ideas. The effectiveness of the strategy is shown in the final example where the supervision of an eight-tank interconnected system is considered.

Distributed Coordination Strategies for Interconnected Multi-Agent Systems

In this paper we present a novel distributed supervision strategy for multi-agent linear systems connected via data networks and subject to coordination constraints. Such a coordination-by-constraint paradigm is based on an on-line active set-point management and is characterized by a set of spatially distributed dynamic systems, connected via communication channels, with possibly dynamical coupling amongst them which need to be supervised and coordinated in order to accomplish their overall objective. Two distributed strategies will be fully described and analyzed. First, we will propose a “sequential” distributed strategy in which only one agent at the time is allowed to manipulate its own reference signal. Such a strategy will be instrumental to introduce a more effective “parallel” distributed strategy, in which all agents are allowed, under certain conditions, to modify their own reference signals simultaneously. To show the effectiveness of the proposed methods, the distributed coordination of dynamically coupled autonomous vehicles under input-saturation and formation accuracy constraints is presented.

Coordinative constraints in bimanual tool use

This study investigates coordinative constraints when participants execute discrete bimanual tool use actions. Participants moved two levers to targets that were either presented near the proximal parts of the levers or near the distal tips of the levers. In the first case, the tool transformation (i.e. the relationship between hand movement direction and target direction) was compatible, whereas in the second case, it was incompatible. We hypothesized that an egocentric constraint (i.e. a preference for moving the hands and tools in a mirror-symmetrical fashion) would be dominant when targets are presented near the proximal parts of the levers because in this situation, movements can be coded in terms of body-related coordinates. Furthermore, an allocentric constraint (i.e. a preference to move the hands in the same (parallel) direction in extrinsic space) was expected to be dominant when one of the targets or both are presented near the distal parts of the levers because in this condition, movements have to be coded in an external reference frame. The results show that when both targets are presented near the proximal parts of the levers, participants are faster and produce less errors with mirror-symmetrical when compared to parallel movements. Furthermore, the RT mirror-symmetry advantage is eliminated, when both targets are presented near the distal parts of the levers, and it is reversed, when the target for one lever is presented near its distal part and the target for the other lever is presented near its proximal part. These results show that the dominance of egocentric and allocentric coordinative constraints in bimanual tool use depends on whether movements are coded in terms of body-related coordinates or in an external reference frame.

Optimal Coordination of Directional Overcurrent Relays Considering Different Network Topologies Using Interval Linear Programming

In real power systems, the network topology is subjected to uncertainty due to single-line outage contingencies, maintenance activities, and network reconfigurations. These changes in the network topology may lead to miscoordination of directional overcurrent relays (DOCRs). To overcome this drawback, corresponding to each primary/backup relay pair, a set of inequality coordination constraints which is related to different network topologies should be satisfied. In this paper, a new approach based on the interval analysis is introduced to solve the DOCRs coordination problem considering uncertainty in the network topology. The basic idea is to convert the set of inequality constraints corresponding to each relay pair to an interval constraint. In this situation, the DOCR coordination problem is formulated as an interval linear programming (ILP) problem. Using well-known mathematical theorems, the obtained ILP problem, which has no equality constraints, can be converted to standard linear programming (LP). As a result, the number of coordination constraints is significantly reduced in the proposed methods. The application of the proposed method to the IEEE 14- and 30-bus test systems proves the ability of the interval method in modeling topology uncertainty in the large-scale coordination problem.

On the Nature of the Quotative Operator Movement and the CSC Obviation Effects

The quote initial reported direct speech optionally involves subject-main verb inversion, and the inverted cases are called the quotative inversion construction. This study examines the structure of this quotative inversion and non-inversion constructions and diagnoses one previously unnoticed problem in them. More specifically, it will be shown that the quotative operator, widely believed to be involved in the derivation of the quotative constructions, is immune to the Coordinate Structure Constraint. This obviation effect is attributed to the A-movement nature of the quotative operator movement, based on the idea that A-movement is immune to the Coordinate Structure Constraint.

Considering Different Network Topologies in Optimal Overcurrent Relay Coordination Using a Hybrid GA

The directional overcurrent relays (DOCRs) coordination problem is usually studied based on a fixed network topology in an interconnected power system, and is formulated as an optimization problem. In practice, the system may be operated in different topologies due to outage of the transmission lines, transformers, and generating units. There are some situations for which the changes in the network topology of a system could cause the protective system to operate without selectivity. The aim of this paper is to study DOCRs coordination considering the effects of the different network topologies in the optimization problem. Corresponding to each network topology, a large number of coordination constraints should be taken into account in the problem formulation. In this situation, in addition to nonlinearity and nonconvexity, the optimization problem experiences many coordination constraints. The genetic algorithm (GA) is selected as a powerful tool in solving this complex and nonconvex optimization problem. In this paper, in order to improve the convergence of the GA, a new hybrid method is introduced. The results show a robust and optimal solution can be efficiently obtained by implementing the proposed hybrid GA method.

Distributed Coordination-by-Constraint Strategies for Networked Control Systems

In this paper we present preliminary ideas on how to develop distributed supervision strategies for networked control systems subject to coordination constraints to be enforced on-line. Such a coordination paradigm, hereafter referred to as coordination-by-constraint, is characterized by a set of spatially distributed dynamic systems, connected via communication channels, with possibly dynamical coupling amongst them which need to be supervised and coordinated in order to accomplish their overall objective. In order to evaluate the distributed method here proposed, the distributed coordination of coupled autonomous vehicles under input-saturation and formation accuracy constraints is presented as an example.

Coordination of complex bimanual multijoint movements under increasing cycling frequencies: The prevalence of mirror-image and translational symmetry

The present study examined the principles underlying inter and intralimb coordination constraints during performance of bimanual elbow–wrist movements at different cycling frequencies (from 0.75 Hz to 2.50 Hz). Participants performed eight coordination tasks that consisted of a combination of in-phase (IN) and/or anti-phase (AN) coordination modes between both elbows and wrists (interlimb), with isodirectional (Iso) or non-isodirectional (NonI) coordination modes within each limb (intralimb). As expected, the principle of muscle homology (in-phase coordination), giving rise to mirror symmetrical movements with respect to the mid-sagittal plane, had a powerful influence on the quality of global coordinative behavior both between and within limbs. When this principle was violated (i.e., when the anti-phase mode was introduced in one or both joint pairs), the non-isodirectional intralimb mode exhibited a (de)stabilizing role in coordination, which became more pronounced at higher cycling frequencies. However, pattern loss with increasing cycling frequency resulted not only in convergence toward the more stable in-phase patterns with the elbows and wrists but also to the anti-phase patterns (which were associated with directional compatibility of within-limb motions). Moreover, participants generally preserved their initial mode of coordination (either in-phase or anti-phase) in the proximal joints (i.e., elbows) while shifting from anti-phase to in-phase (or vice versa) with their distal joint pair (i.e., wrists). Taken together, these findings reflect the impact of two immanent types of symmetry in bimanual coordination: mirror-image and translational symmetry.