System response time effects on user productivity

The present study tested the proposal that reducing computer system response times from a few seconds to sub-second levels results in dramatic increases in user productivity. Subjects completed data-entry and problem-solving tasks using a computer statistical package, under a range of computer response times from 0⋅1 to 5 seconds. Results indicated that some increase in productivity does occur as system response time decreases; however, (1) the size of the effect is considerably smaller than previously indicated, (2) the effect occurred only for data-entry tasks, disappearing in problem-solving situations and declining in strength as the data-entry task became more complex, and (3) the relationship between response time and productivity was linear rather than exponential, as was indicated previously. These results suggest that an attentional'automatic processing model of the user is more appropriate than a model proposing that users do not need time to think between entries to the computer.     

Analyzing the effects of emotion management on time and self-management in computer-based learning

Emotional learning involves the acquisition of skills to recognize and manage emotions, develop care and concern for others, make responsible decisions, establish positive relationships, and handle challenging situations effectively. Time is an important variable in learning context and especially in the analysis of teaching-learning processes that take place in collaborative learning, whereas time management is crucial for effective learning. The aim of this work has been to analyze the effects of emotion management on time and self-management in e-learning and identify the competencies in time and self-management that are mostly influenced when students strive to achieve effective learning. To this end, we run an experiment with a class of high school students, which showed that increasing their ability to manage emotions better and more effectively enhances their competency to manage the time allocated to the learning practice more productively, and consequently their learning performance in terms of behavioral engagement and achievement and partly, in terms of cognitive engagement and self-regulation. Teacher affective feedback was proved to be a crucial factor to enhance cognitive engagement.     

Scheduling parallelizable tasks to minimize make-span and weighted response time

This paper presents a generalization to classical scheduling theory by removing the restriction that only one processor can work on a given task at a particular time. Instead, it is assumed that each task can be allocated any number of identical processors from one to the maximum number available, with each task's completion time being a function of the number of processors allocated. Tasks may be started any time, but once started, a task must not have its processor allocation altered or be preempted. Two objective functions are considered: minimizing the overall completion time for the tasks (make-span) and minimizing a weighted sum of the task completion times (weighted response). Both are considered subject to a constraint on the total number of processors available. Suboptimal algorithms are developed for both of these NP-hard problems using Lagrangian relaxation, and their performances are analyzed through extensive simulations. Duality gaps for all problems tested ranged from under 1% to 92%, depending more on the problem size than the specific problem.     

On-line terminal response time: The effects of background activity

This paper reports on a set of experiments to determine the effects on the response time of an on-line system when different typs of jobs run in the background partition. Since many applications may be better served by an on-line system but do not justify a dedicated system, it is frequently necessary to run batch jobs in the background partition of a computer supporting an on-line system. Substantial differences in terminal response time were observed depending on what jobs were scheduled in the background partitions. The computer manager should be aware of these factors when scheduling such batch work.     

The use of key-press,voice and mouse devices in response time researches: A comparison in low conflict tasks

It is implicitly assumed that data obtained from different modalities in response time research are comparable. However, this assumption has not been tested and verified, and scholars do not really know whether their choice has any effect on data, and consequently, whether they have lost experimental control. This research compares three modes (key-press, voice and mouse) in three of the most commonly used low conflict tasks (simple reaction, lexical decision and semantic categorization) to confirm the above assumption. To gain more precision, linguistic and semantic gradients have been tested. Results show that there are no functional differences in the simple reaction task. In the lexical decision task a frequency effect for all modes has been found. Specific S–R mapping rules do not need to be reversed when using a button-press or a mouse mode, but they have effects on the voice mode. In the semantic categorization task, a gradient and a frequency effect have been found in all modes. However, word frequency can affect the data. It is recommended to reverse S–R mapping rules in the voice mode in order to avoid differences with the manual modes. In conclusion, differences in low conflict tasks exist and must be taken into consideration when comparing studies in which different devices have been used.     

Worst-case response time analysis of real-time tasks under fixed-priority scheduling with deferred preemption

Fixed-priority scheduling with deferred preemption (FPDS) has been proposed in the literature as a viable alternative to fixed-priority pre-emptive scheduling (FPPS), that obviates the need for non-trivial resource access protocols and reduces the cost of arbitrary preemptions. This paper shows that existing worst-case response time analysis of hard real-time tasks under FPDS, arbitrary phasing and relative deadlines at most equal to periods is pessimistic and/or optimistic. The same problem also arises for fixed-priority non-pre-emptive scheduling (FPNS), being a special case of FPDS. This paper provides a revised analysis, resolving the problems with the existing approaches. The analysis is based on known concepts of critical instant and busy period for FPPS. To accommodate for our scheduling model for FPDS, we need to slightly modify existing definitions of these concepts. The analysis assumes a continuous scheduling model, which is based on a partitioning of the timeline in a set of non-empty, right semi-open intervals. It is shown that the critical instant, longest busy period, and worst-case response time for a task are suprema rather than maxima for all tasks, except for the lowest priority task. Hence, that instant, period, and response time cannot be assumed for any task, except for the lowest priority task. Moreover, it is shown that the analysis is not uniform for all tasks, i.e. the analysis for the lowest priority task differs from the analysis of the other tasks. These anomalies for the lowest priority task are an immediate consequence of the fact that only the lowest priority task cannot be blocked. To build on earlier work, the worst-case response time analysis for FPDS is expressed in terms of known worst-case analysis results for FPPS. The paper includes pessimistic variants of the analysis, which are uniform for all tasks, illustrates the revised analysis for an advanced model for FPDS, where tasks are structured as flow graphs of subjobs rather than sequences, and shows that our analysis is sustainable.     

Aging and response selection in spatial choice tasks

Factors that make response selection more difficult, most notably incompatibility between displays and controls, degrade performance. The cost of incompatibility on performance is often much greater for older than for younger adults. To design products that accommodate decreased response selection capabilities of older adults, designers need to understand the specific ways in which response selection processes change with age. The purpose of the present paper is to review research on age-related changes in stimulus-response compatibility and response precuing effects, the two effects that are most directly linked to basic response selection processes. Several specific aspects of response selection that are particularly harmful for older adults' performance are identified. Potential applications of this research include initial guidelines for minimizing the effects of those aspects when designing for older adults.     

Partitioning of Independent Tasks for Minimizing Completion Time and Total Waiting Time

Parallel processors provide fast computing environments for various users.But the real efficiencies of parallel processors intensively depend on the partitioning strategies of tasks over the processors.In this paper,the partitioning problems of independent tasks for homogeneous system of parallel processors are quantitatively studied.We adopt two criteria,minimizing the completion time and the total waiting time, to determine the optimal partitioning strategy.     

一种提高数据库响应时间方法的研究

数据库监控是保证数据库性能稳定的有效方法，而响应时间是衡量数据库系统性能的重要指标。本文在数据库监控的基础上，提出了用数学结合图形化的方法，封有问题的SQL语句追行性能分析，进而提高数据库的响应时间。     

University students and career decidedness: effects of two computer-based career guidance interventions

The DISCOVER Program (American College Testing Program, 1995) is a widely used computer-assisted guidance program that reportedly increases career decidedness by providing users with a computer generated list of occupations representing a congruent fit between the individual's personality and possible work environments. A review of the literature, however, suggested a need for additional research exploring the effectiveness of DISCOVER with and without counselor intervention with various populations grouped by combinations of age, sex, and race.This article describes the effects of a counselor-plus-computer and computer-only intervention on increasing the level of career decidedness in a sample population of university students. Results of the study indicate that both the computer-only and counselor-plus-computer experimental conditions were significantly different from the delayed treatment control group. The results further indicate that the counselor-plus-computer experimental condition was significantly different from both the delayed treatment control group and the computer-only experimental condition group. No significance was found when controlling for age, gender, and race. Implication of the study's findings are discussed.     

Driving in an urban environment,the stress response and effects of exercise

Driving may be detrimental to health, with one hypothesis suggesting that driving may elicit an acute stress response and, with repeated exposures, may become a chronic stressor. The present study examined the stress response to driving and the effectiveness of a prior exercise bout in dampening this response. Twenty healthy adults performed three tasks: control, driving and exercise plus driving. Heart rate (HR), heart rate variability (HRV), blood pressure (BP) and cortisol were measured to quantify the acute stress response to each condition. Data indicated a stress response to driving: HR was elevated and HRV was reduced during the driving task compared with control. HR was elevated and HRV was reduced comparing the exercise plus driving with the driving condition. BP and cortisol were not different among conditions. The potential of interventions, such as exercise, to counter daily stressors should be evaluated to safeguard long-term health.

Practitioner Summary: this study confirms that driving induces a stress response, with the exercise intervention providing mixed results (an increase in cardiovascular measures and a decrease in cortisol measure trending significance). Given the known consequences of stress and evidence that exercise can mitigate acute stress, further evaluation of exercise interventions is recommended.     

The effects of simulating human conversational style in a computer-based interview

A computer interview involves a program asking questions of the user, who responds by providing answers directly to the computer. Using a computer interview has been shown to be an effective method of eliciting information, and particularly personal information which many people find difficult to discuss face to face. While the simulation of some of the characteristics of human–human communication seems to enhance the dialogue, it appears to be the absence of others, such as being non-judgmental, unshockable, completely consistent, and unendingly patient, that gives computer interviewing its particular effectiveness.

The work reported in this paper investigated the effect of simulating in a computer interview two techniques which good human interviewers use: empathy and grouping questions. Thirty nine interviewees answered 40 questions on a computer, in combinations of human-like or computer-like question styles, and presented in either a logical or a random order.

They found the use of the human interviewer technique in the wording of questions made the computer interviews more interesting and enjoyable, than when blunt, direct questioning was used, and they answered honestly more often to the human-like style.

This investigation has shown that a computer interview can be made more effective by simulating the human interviewer technique of empathising with interviewees and softening those questions which are of a sensitive nature. It seems therefore that it is the combination of the right non-human characteristics with the right human characteristics that can produce a successful computer interview. The question for further research is which are the right characteristics in each case, given the purpose of the interview.     

Two urinary catecholamine measurement indices for applied stress research: effects of time and temperature until freezing

Research on stress at work often involves the analysis of urinary adrenaline and noradrenaline. It is usually assumed that samples have to be cooled quickly and stored at refrigerator temperature before freezing. This is often difficult to achieve in field studies. This experimental study therefore tests the robustness of results when samples are not cooled immediately. Samples of 9 men and women, collected at 3 points in time, were immediately frozen, kept for a variable delay in a warm room, or stored in a refrigerator before freezing. Two indices were calculated: (a) the ratio of hormones to liquid volume, period of excretion, and body weight; and (b) the ratio of hormones to urinary creatinine. The reliability of high performance liquid chromatography analysis was satisfactory, as was the comparability of the 2 indices. Unfavorable storage up to 24 hr did not cause bacteria-driven decreases of catecholamines, regardless of storage temperature or sampling time. Results suggest high stability for at least 24 hr without cooling, provided the samples are immediately acidified. Cooling may therefore be handled less restrictively than has been assumed. The application of this research is to facilitate research in settings where samples are collected at different places, such as participants' homes or different workplaces.     

Dynamic response topology optimization in the time domain using model reduction method

The dynamic response topology optimization problems are usually computationally expensive, so it is necessary to employ the model reduction methods to reduce computational cost. This work will investigate the effectiveness of the mode displacement method(MDM) and mode acceleration method(MAM) for time-domain response problems within the framework of density-based topology optimization. Three objective functions, the mean dynamic compliance, mean strain energy and mean squared displacement are considered. It is found that, in general cases, MDM is not suitable for time-domain response topology optimization problems due to its low accuracy of approximation, while MAM works well for problems of a wide range, and when there are many time steps, the MAM based topology optimization approach is more efficient than the direct integration based approach. So for practical applications, when the problem needs many time steps, the MAM based approach is preferred and otherwise, the direct integration based approach is suggested.     

A method for obtaining the time response of any linear system

A simple method is presented for obtaining the time response of any time-invariant linear system for zero or nonzero initial conditions and for inputs which can be expressed analytically. The method, in addition to its use in obtaining total solutions, is also useful in engineering education and industrial practice in learning how the basic types of transfer functions contribute to total system dynamics. Furthermore, as one's experience with this method increases, competence is gained in estimating the form of the total solution from an observation of the system transfer function and time input.     

Resampling data on a time axis in tasks of revealing regularities

A framework is proposed for revealing and sharpening discriminative regularities in data. Noninvariance of the data sample with respect to transformations of this or that type is used as indicator of the presence of some useful regularity or dependency. Weak regularities are emphasized by deletion from the time axis of all results of consecutive trials which form maximal invariant subset. The text was submitted by the author in English. Alexander Vinogradov. Vinogradov was born in 1951. He graduate from Moscow Institute of Physics and Technology in 1974 and earned the candidate degree in mathematical cybernetics in 1978. His main sphere of interests is geometric and algebraic methods in data analysis and image processing. He is the author of about 50 scientific publications. He is married and has a son and a daughter.     

Learning and transfer effects in simulated industrial information processing tasks

Practice and alternation among a set of jobs are the characteristics of any jobbing industry. Learning and transfer of learning, which are the main human factors issues in practice and alternation, were investigated through laboratory simulation of two typical industrial information processing tasks. In the first experiment a location task was examined while a search task was investigated in experiment two. In both experiments two levels of task complexity, two groups of subjects, and two positions were combined in a 2 × 2 latin square formation with 800 trials in each task level. The results show that learning pattern appears to be task dependent, with quicker learning in location tasks than in search tasks. Learning also transfers differently for the tasks considered. Implications for the industrial training program for assembly tasks are discussed.     

Interaction effects in simultaneous motor control and movement perception tasks

Recent findings in neuroscience suggest an overlap between those brain regions involved in the control and execution of movement and those activated during the perception of another’s movement. This so called ‘mirror neuron’ system is thought to underlie our ability to automatically infer the goals and intentions of others by observing their actions. Kilner et al. (Curr Biol 13(6):522–525, 2003) provide evidence for a human ‘mirror neuron’ system by showing that the execution of simple arm movements is affected by the simultaneous perception of another’s movement. Specifically, observation of ‘incongruent’ movements made by another human, but not by a robotic arm, leads to greater variability in the movement trajectory than observation of movements in the same direction. In this study we ask which aspects of the observed motion are crucial to this interference effect by comparing the efficacy of real human movement to that of sparse ‘point-light displays’. Eight participants performed whole arm movements in both horizontal and vertical directions while observing either the experimenter or a virtual ‘point-light’ figure making arm movements in the same or in a different direction. Our results, however, failed to show an effect of ‘congruency’ of the observed movement on movement variability, regardless of whether a human actor or point-light figure was observed. The findings are discussed, and future directions for studies of perception-action coupling are considered.     

Content and representation effects with reasoning tasks in PROLOG form

Two experiments were carried out to examine human reasoning performance in the context of the logic programming language PROLOG. Two factors, 'content' (familiar versus unfamiliar) and 'representation' (diagrammatic versus PROLOG-like list) were investigated. Subjects answered questions about hierarchical relationships in each condition. A significant interaction was obtained in both experiments, subjects making fewer errors in the familiar-diagram and unfamiliar-list conditions than in the familiar-list and unfamiliar-diagram conditions.

It is hypothesized that a lower percentage of correct responses was given in familiar-list and unfamiliar-diagram conditions because the representation of information prevented successful use of an appropriate reasoning strategy. Working memory limitations provide a basis for understanding constraints on reasoning strategies for solving task questions. These strategies may involve either a serial or a spatial solution process. One strategy may require a larger working memory load than another, depending on the representation and content of the task information. Implications for PROLOG programming instruction are discussed.