scholarly journals Fitts' law is not continuous in reciprocal aiming

2009 ◽  
Vol 277 (1685) ◽  
pp. 1179-1184 ◽  
Author(s):  
Raoul Huys ◽  
Laure Fernandez ◽  
Reinoud J. Bootsma ◽  
Viktor K. Jirsa

It takes longer to accomplish difficult tasks than easy ones. In the context of motor behaviour, Fitts' famous law states that the time needed to successfully execute an aiming movement increases linearly with task difficulty. While Fitts' explicit formulation has met criticism, the relation between task difficulty and movement time is invariantly portrayed as continuous. Here, we demonstrate that Fitts' law is discontinuous in reciprocal aiming owing to a transition in operative motor control mechanisms with increasing task difficulty. In particular, rhythmic movements are implemented in easy tasks and discrete movements in difficult ones. How movement time increases with task difficulty differs in both movement types. It appears, therefore, that the human nervous system abruptly engages a different control mechanism when task difficulty increases.

2019 ◽  
Vol 121 (2) ◽  
pp. 574-587 ◽  
Author(s):  
Zhaoran Zhang ◽  
Dagmar Sternad

This study examined how humans spontaneously merge a sequence of discrete actions into a rhythmic pattern, even when periodicity is not required. Two experiments used a virtual throwing task, in which subjects performed a long sequence of discrete throwing movements, aiming to hit a virtual target. In experiment 1, subjects performed the task for 11 sessions. Although there was no instruction to perform rhythmically, the variability of the interthrow intervals decreased to a level comparable to that of synchronizing with a metronome; furthermore, dwell times shortened or even disappeared with practice. Floquet multipliers and decreasing variability of the arm trajectories estimated in state space indicated an increasing degree of dynamic stability. Subjects who achieved a higher level of periodicity and stability also displayed higher accuracy in the throwing task. To directly test whether rhythmicity affected performance, experiment 2 disrupted the evolving continuity and periodicity by enforcing a pause between successive throws. This discrete group performed significantly worse and with higher variability in their arm trajectories than the self-paced group. These findings are discussed in the context of previous neuroimaging results showing that rhythmic movements involve significantly fewer cortical and subcortical activations than discrete movements and therefore may pose a computationally more parsimonious solution. Such emerging stable rhythms in neuromotor subsystems may serve as building blocks or dynamic primitives for complex actions. The tendency for humans to spontaneously fall into a rhythm in voluntary movements is consistent with the ubiquity of rhythms at all levels of the physiological system. NEW & NOTEWORTHY When performing a series of throws to hit a target, humans spontaneously merged successive actions into a continuous approximately periodic pattern. The degree of rhythmicity and stability correlated with hitting accuracy. Enforcing irregular pauses between throws to disrupt the rhythm deteriorated performance. Stable rhythmic patterns may simplify control of movement and serve as dynamic primitives for more complex actions. This observation reveals that biological systems tend to exhibit rhythmic behavior consistent with a plethora of physiological processes.


Author(s):  
Errol R. Hoffmann

Two tasks in which subjects aim at an array of devices were considered: moving to one knob within an array and moving the finger on a numeric keypad. It was shown by a mathematical model based on Fitts' law, that when the array density is specified for the array of knobs or keys, there is an optimum control size for minimum movement time. The theoretical result was obtained by considering a two-element model of the movement, the first being a reach to the general location of the control and the second describing the insertion of the fingers into the space between adjacent controls. As the first element has a movement time that decreases with increase of control size and the second a time increasing with control size, there is an optimum control size where the movement time is a minimum.


Author(s):  
Shang H. Hsu ◽  
Chien C. Huang

The purpose of this study was to investigate the effects of target width, movement direction, movement amplitude, and remote distance on remote positioning performance. Movement time and movement distance ratio were taken as measures of remote positioning performance. It was found that the effects of target width, movement amplitude, and movement direction on the two measures were significant. The effect of remote distance was significant only for movement distance ratio. The magnitude of the effect of target width on movement time was larger than that of movement amplitude; a modification of Fitts' Law was thus proposed. Moreover, there was an interactive effect between target width and movement direction- i.e., movement direction had an effect only when the target width was small. Among the eight movement directions, upward vertical movement was the best for remote positioning. The results shed some light onto the design of remote control user interface.


Author(s):  
С.В. Шевелев ◽  
А.Б. Семенов

Рассмотрены принципы обеспечения заданного уровня качества обслуживания QoS в беспроводных сетях, позволяющие достигнуть устойчивого функционирования программных приложений реального времени за счет тонкой настройки приоритезации генерируемого ими трафика. Основное внимание уделяется механизму управления доступом на основе конкуренции и контролируемого доступа, а также их расширениям. Затронуты вопросы инкапсуляции базовых механизмов управления в решения более высоких уровней EDCA и TXOP. Приведены расчетные значения соответствующих параметров. The principles of ensuring a given level of quality of QoS service in wireless networks are considered, which allow achieving the stable functioning of real-time software applications by fine-tuning the prioritization of the traffic generated by them. The main focus is on the competition-based access control mechanism and controlled access, as well as their extensions. The issues of encapsulation of basic control mechanisms in solutions of higher levels of EDCA and TXOP are touched upon. The calculated values of the corresponding parameters are given.


2019 ◽  
Vol 24 (6) ◽  
pp. 580-595 ◽  
Author(s):  
Lan Li ◽  
Gang Li ◽  
Shui F. Chan

Purpose The purpose of this paper is to examine, within a context of manufacturing transformation, whether corporate responsibility for employees (CRE) promotes the service innovation performance (SIP) of the firm; whether this effect is mediated by employee innovative behavior (EIB), and how two control mechanisms (process-control (PC) and outcome-control mechanism) moderate the relationship. Design/methodology/approach Drawing on social exchange and control mechanism theory, this paper establishes a conceptual model and adopts a hierarchical regression analysis to examine the model with a sample of 110 manufacturing firms from China. Findings The study finds that CRE positively affects SIP. EIB mediates such effect. Output-control weakens the effect of CRE on EIB, and PC does not impact on the relationship. Practical implications The findings suggest that, facing tremendous pressure in manufacturing transformation, firms must be cautious in treating their employees. Given that EIB is crucial to improving the SIP, and in turn to meet the ever upgrading customer demands, firms ought to actively take responsibilities to protect employees’ interests, and cautiously adopt control mechanisms. Thus employees could be motivated to involve in service innovation actively. This effect not only benefits employees with a sustainable career but also help the firm survive in this tough transformation period. Originality/value This study is one of the first (if any) research that examining the impact of CRE on SIP and EIB. The findings are an extension of the existing research, and show the explanation potential of corporate social responsibility on EIB and SIP in a difficult time such as manufacturing transformation.


Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 283
Author(s):  
Fawad Ali Khan ◽  
Rafidah Md Noor ◽  
Miss Laiha Mat Kiah ◽  
Ismail Ahmedy ◽  
Mohd Yamani ◽  
...  

Internet of Things (IoT) facilitates a wide range of applications through sensor-based connected devices that require bandwidth and other network resources. Enhancement of efficient utilization of a heterogeneous IoT network is an open optimization problem that is mostly suffered by network flooding. Redundant, unwanted, and flooded queries are major causes of inefficient utilization of resources. Several query control mechanisms in the literature claimed to cater to the issues related to bandwidth, cost, and Quality of Service (QoS). This research article presented a statistical performance evaluation of different query control mechanisms that addressed minimization of energy consumption, energy cost and network flooding. Specifically, it evaluated the performance measure of Query Control Mechanism (QCM) for QoS-enabled layered-based clustering for reactive flooding in the Internet of Things. By statistical means, this study inferred the significant achievement of the QCM algorithm that outperformed the prevailing algorithms, i.e., Divide-and-Conquer (DnC), Service Level Agreements (SLA), and Hybrid Energy-aware Clustering Protocol for IoT (Hy-IoT) for identification and elimination of redundant flooding queries. The inferential analysis for performance evaluation of algorithms was measured in terms of three scenarios, i.e., energy consumption, delays and throughput with different intervals of traffic, malicious mote and malicious mote with realistic condition. It is evident from the results that the QCM algorithm outperforms the existing algorithms and the statistical probability value “P” < 0.05 indicates the performance of QCM is significant at the 95% confidence interval. Hence, it could be inferred from findings that the performance of the QCM algorithm was substantial as compared to that of other algorithms.


Author(s):  
Kenneth Nemire

Effects of visual and auditory display enhancements to a pick-and-place task performed in an immersive virtual environment were evaluated to determine whether the enhancements may replace depth information provided by stereoscopic visual displays. Participants used a commercial head-mounted display, spatial trackers on the head and hand, and a control wand. Independent variables included biocular or stereo viewing, movement amplitude, target diameter, and audio or visual enhancements. Dependent variables were movement time and number of discrete movements required to complete the task. Results indicated the stereo display and the display enhancements provided no performance advantages over the biocular display for the easier task conditions. Further, visual and auditory enhancements to the biocular display were found that resulted in performance that was not different from using stereoscopic displays. Implications of the results are discussed.


2012 ◽  
Vol 49 (No. 6) ◽  
pp. 275-277
Author(s):  
P. Moulis

There is a&nbsp;lot of available investigations in the area of company crisis reasons problems nowadays. These inquiries were summarised into the indicators of company crisis reasons. The development and level of these indicators is not possible to consider to be company crisis reasons but above all to be its manifestation. The veritable reason of crisis is the absence of effective control mechanisms in the company, especially of the &ldquo;natural&rdquo; control mechanisms. The natural control mechanism means such as rises from the substance of joint stock companies (respectively legal rules of joint stock company). There is a&nbsp;presumption of control activities interaction among the General Assembly, Supervisory Board and Board. Control mechanisms work on the common economic principles&rsquo; base in this sense and it means that the owner is considered to be the primary managing element and the management acts as the derivative managing element. The assumption of effective economic principles functioning is the existence of standard variable of these relations i. e. the existence of relevant interests.


1997 ◽  
Vol 20 (2) ◽  
pp. 312-313
Author(s):  
Herbert Heuer

Movement time and accuracy, as defined by Plamondon & Alimi, do not conform to empirical definitions. When definitions are used that conform better to empirical ones, the original predictions of the kinematic theory are no longer valid – as is demonstrated by simulations. Thus the theoretically derived quadratic law and the successful empirical quadratic law seem to be independent of each other.


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