Effects Of Line Length Research Articles

Line Length Effect on Electromigration Characteristics of Eutectic SnPb Solder

A deoxidized low-phosphorous copper processed by eight cycles of accumulative roll-bonding (ARB) was annealed at various temperatures ranging from 100 to . The annealed copper was characterized by transmission electron microscopy (TEM) and tensile & hardness test. TEM observation revealed that the ultrafine grains developed by the ARB still remained up to , however above they were replaced by equiaxed and coarse grains due to an occurrence of the static recrystallization. The hardness of the copper decreased slightly with the annealing temperature up to , however they dropped largely above . Annealing characteristics of the copper were compared with those of an oxygen free copper processed by ARB and subsequently annealed.

Saliency from orthogonal velocity component in texture segregation

We found that a moving target line, more-vertical than 45 deg-oriented background lines, pops-out ( d′ = 1.2) although it moves at the same speed of background elements and although it is invisible in static presentation ( d′ = .7). We suggest that the moving more-vertical target is more salient because the motion system responds to the orthogonal-velocity-component ( V ⊥ = Δ d/Δ t sin Θ) that is larger for the more-vertical target than for distracters. However, motion does not produce high d′ when the target is more horizontal than background ( d′ = .6). This result is not expected if saliency resulted from the sum of saliency of orientation and motion independently coded but is instead predicted by visual search asymmetry. A line length effect on the moving target saliency also suggests that V ⊥ is extracted on the whole line and this operation is facilitated by line length in the same way for more-vertical and more-horizontal targets. Altogether, these results demonstrate that speed-based segmentation operating on V ⊥ not only affects speed and direction of motion discrimination, as previously demonstrated, but accounts for high saliency of image features that would otherwise prove undetectable of the basis of orientation-contrast.

Weights and measures: A new look at bisection behaviour in neglect

Horizontal line bisection is a ubiquitous task in the investigation of visual neglect. Patients with left neglect typically make rightward errors that increase with line length and for lines at more leftward positions. For short lines, or for lines presented in right space, these errors may ‘cross over’ to become leftward. We have taken a new approach to these phenomena by employing a different set of dependent and independent variables for their description. Rather than recording bisection error, we record the lateral position of the response within the workspace. We have studied how this varies when the locations of the left and right endpoints are manipulated independently. Across 30 patients with left neglect, we have observed a characteristic asymmetry between the ‘weightings’ accorded to the two endpoints, such that responses are less affected by changes in the location of the left endpoint than by changes in the location of the right. We show that a simple endpoint weightings analysis accounts readily for the effects of line length and spatial position, including cross-over effects, and leads to an index of neglect that is more sensitive than the standard measure. We argue that this novel approach is more parsimonious than the standard model and yields fresh insights into the nature of neglect impairment.

The influence of font type and line length on visual search and information retrieval in web pages

Most web sites are heavily text-based. Previous research has indicated that the way in which this text is presented may have a significant impact on usability. This paper reports findings from two experiments that explored the influence of font type and line length on a range of performance and subjective measures. Experiment 1 used a visual search task and Experiment 2 examined information retrieval. Overall, there was little impact of font on task performance, although the effect of line length was significant, with longer line lengths facilitating better scanning (Experiment 1) and shorter line lengths leading to better subjective outcomes (Experiments 1 and 2). Implications of these results for the design of web pages are discussed and recommendations given.

The Effects of Line Length on Reading Performance of Online News Articles

Previous research has shown that typographical factors of online text may influence its readability. This study examines the effects of line length on reading speed, comprehension, and user satisfaction of online news articles. Twenty college-age students read news articles displayed in 35, 55, 75, or 95 characters per line (cpl) from a computer monitor. Comprehension was assessed using six question types — title, main idea, main factual, structure, incidental, and recognition (Dyson & Haselgrove, 2001). Results showed that passages formatted with 95 cpl resulted in faster reading speed. Structure questions were found to be more challenging overall when compared to factual and other lower-level questions. Overall satisfaction was not affected by line length; however, users indicated a strong preference for the extreme line lengths.

Peripersonal spatial attention in children with spina bifida: Associations between horizontal and vertical line bisection and congenital malformations of the corpus callosum, midbrain, and posterior cortex

Horizontal and vertical line bisection was studied in 129 children and adolescents between 8 and 19 years of age, one group ( n = 32) of typically developing controls and one group ( n = 97) with spina bifida (SBM), a neurodevelopmental disorder associated with dysmorphology of the corpus callosum, posterior cortex, and midbrain. For each participant, structural brain MRIs were analyzed qualitatively to identify beaking of the midbrain tectum and corpus callosum agenesis and hypoplasia and quantitatively by segmentation and volumetric analyses of regional cortical white and gray matter. Each group showed the line length effect, whereby greater estimation errors are made with longer lines. The group with SBM differed from controls in terms of both accuracy and variability of line bisection. Children with SBM showed pseudoneglect, attending more than controls to left hemispace. The extent of rightward bisection bias was unrelated to right posterior brain volumes, although an intact corpus callosum during development moderated and normalized the exaggerated leftward line bisection bias. More children with SBM than controls attended to inferior hemispace. A normal midbrain and greater posterior cortex volume during development moderated and normalized the downward bias. Children with SBM showed more intra-subject variability than controls. Line bisection in children with SBM reflects three deficits: an exaggerated attentional bias to left hemispace, an abnormal attentional bias to inferior hemispace; and a larger zone of subjective uncertainty in bisection judgments.

Electromigration behavior of dual-damascene Cu interconnects––Structure, width, and length dependences

Experiments were performed to study the effect of line width and length, and the results revealed interesting differences in electromigration behavior of via-fed upper and lower layer dual-damascene test structures. The observed location of electromigration induced void in upper and lower layer test structures cannot be completely explained by the theory of current gradient induced vacancy diffusion. The electromigration median time to failure (MTF) were found to be dependent upon the line width for the lower layer test structures while it remained unaffected in the case of upper layer test structure. Cu/dielectric cap interface acting as the dominant electromigration path and the current crowding location being near the Cu/dielectric cap interface for lower layer structures due to structural differences, explain this behavior. Similarly, short length upper and lower layer test structures exhibited completely different characteristics. The back stress effect on short lines was evident on both upper and lower layer structures, however, only the upper layer showed two distinct via and line failure mechanisms. These observed effects are specific to Cu dual-damascene structures and can have major technological implications for electromigration reliability assessment.

The Effects of Line Length on Children and Adults' Perceived and Actual Online Reading Performance

This study examined reading time, reading efficiency, perceived reading efficiency, and preference for three online-text length conditions, narrow, medium, and full, for both adults and children. No differences were found for either reading time or efficiency for either adults or children. However, adults preferred shorter line lengths to full-screen line lengths. In examining perception of reading efficiency, the results were mixed. For adults, the full text lengths were perceived as providing the optimal amount of scrolling in comparison to the two other narrower line length conditions. The narrowest line length condition was perceived as promoting the highest amount of reader concentration, while the medium line-length condition was considered to be the most optimally presented length for reading. Examining children's perceptions of reading efficiency for each of the line lengths revealed no significant differences in perceived reading efficiency or preference.

Simulating unilateral neglect in normals using prism adaptation: implications for theory

Rightward deviation on line bisection is considered one of the most classic clinical signs of unilateral visual neglect—a cognitive disorder of spatial processing that commonly follows right brain damage. Recently, short-term adaptation to wedge prisms has been shown to significantly reduce neglect on this and other conventional diagnostic tasks. Our previous study has shown that visuomotor adaptation in normals produces a similar pattern of directional bias on a line bisection task. Based on the good working knowledge of how neglect patients perform on different versions of the standard diagnostic task, we showed here that using leftward-deviating prisms in normals, it is possible to produce: (1) a reliable bias on line bisection, (2) a rightward specific deviation, (3) a modulation of rightward deviation, which depends on the relative spatial location of the target lines and (4) a line length effect. A final experiment confirmed that these after-effects are specific to prism adaptation rather than passive prism exposure. Collectively, these findings confirm that adaptation to left-deviating prisms in normals produces a reliable right-sided bias and as shown by a previous visuospatial judgement task, these findings cannot be adequately explained by the symmetric sensori–motor effects of prism adaptation. Taken together with the improvement of spatial neglect shown by right-deviating prisms only, the present study suggests that low level sensori–motor adaptations play a greater role in right hemisphere organisation for spatial cognition than previously thought.

CHARACTERIZATION OF INTRAAORTIC BALLOON PUMP (IABP) TIMING ERRORS USING AN ADULT CARDIOVASCULAR SIMULATOR

We have hypothesized that sources of IABP ineffectiveness are inflation and deflation timing errors due to delays and distortions of the arterial waveform obtained through the fluid-filled lumen of the IABP catheter. Recent human and animal data have confirmed the existence of these errors. Investigating ways to reduce or eliminate these errors and the consequence of the errors may be difficult, if not unacceptably risky, to undertake in human experiments. A controlled, safe and more versatile approach to this problem has been to introduce an adult IABP catheter into the aorta of an adult circulation simulator system. The simulator consists of a pneumatically actuated ventricular sac with trileaflet mitral and aortic valves that approximates the geometry and contraction of the human left ventricle. The instrumented ventricle ejects into instrumented resistance and compliance elements that can be adjusted to create physiologic pressure and flow conditions for the normal and failing left ventricle. The influence of arterial pressure monitoring technique on IABP inflation and deflation timing landmark location and the resulting changes in hemodynamics can be compared along with investigations on the effect of pressure extension line length, bubbles in the fluid line, the size of IABP balloon, the size of the IABP catheter lumen, IABP synchronization rate, and differences in timing strategy.

Line versus representational bisections in unilateral spatial neglect

OBJECTIVESTo clarify the mechanisms of left unilateral spatial neglect found in the bisection of lines after cueing to the left end point and to determine whether neglect occurs for the...

Effects of nonius line and fusion lock parameters on fixation disparity.

Clinical devices for fixation disparity vary in the size and position of the nonius test-lines and in the location of the binocular fusion lock, and published results of studies comparing fixation disparity devices also vary. This study examined how varying stimulus parameters affects the magnitude of horizontal fixation disparity and the precision of nonius alignment in normal observers. Targets were bright vertical lines presented for 150 ms on an oscilloscope and viewed in the dark from 3.95 m through a mirror haploscope. The fusion stimulus was either central, peripheral, or central-plus-peripheral. Fixation disparity was measured for nonius lines with a fixed vertical separation and variable lengths, using the method of constant stimuli. In a second experiment, fixation disparity was assessed for vergence demands of 6delta base-in to 12delta base-out using nonius lines of fixed length and variable vertical separations. For comparison, binocular Vernier thresholds and constant errors were also assessed. Mean values of fixation disparity are invariant with the length and separation of the nonius lines and proximity to the fusion lock, over the range of values tested. When measured with a central fusion lock, the precision of binocular nonius alignment (vergence variability) worsens if the separation between the nonius lines increases beyond approximately 20 min arc. Vergence variability is larger with a peripheral fusion lock for small nonius-line separations and approximately the same as with the central lock for large line separations. Fixation disparity and precision were smallest with a central-plus-peripheral fusion-lock combination. Similar effects of line length and separation were found for binocular Vernier. The finding of invariance of fixation disparity with line length for nonius targets < 1degrees extends those of earlier findings for larger targets. Because the precision of binocular nonius alignment is poorer for large nonius-line separations or with a peripheral fusion lock, fixation disparity should be most repeatable when measured with a central fusion lock and nonius lines separated by 20 min arc or less. However, a peripheral fusion lock and small nonius-line separation may provide the most effective diagnostic combination for fixation disparity.

Orientation Bias in Unilateral Neglect: Representational Contributions

Left-neglect patients bisect horizontal lines to the right of true center. Longer lines are bisected further to the right than shorter lines. This line-length effect might be explained by an increase in the rightward bias of attention because longer lines extend further ipsilesionally. Alternatively, neglect patients might be limited in their abilities to internally represent horizontal magnitudes. Patients might orient further rightward with longer lines because these lines have longer representations. If the line-length effect occurs on lines of identical objective length but they are represented differently, then central mechanisms must contribute to the orientation bias. We constructed two types of lines that were perceived by normal subjects as having different lengths, but were of identical extents. Three neglect patients bisected lines perceived as longer, further to the right than lines perceived as shorter. These results demonstrate that relative magnitudes of internal representations contribute to the degree of bias in neglect patients.

Anisometry of Space Representation in Unilateral Neglect: Empirical Test of a Former Hypothesis

When left-neglect patients are required to extend horizontal segments to double their original length, relative left overextension is frequently observed. Less frequently, relative left underextension may also be found. It was hypothesized that this contrast could depend on the degree of horizontal anisometry of the medium for the representation of spatial properties. The present paper reports an experiment conducted in order to test that hypothesis, on the basis of which left overextension should be larger with shorter than with longer segments and with segments lying in the right rather than in the left hemispace. Although supportive, the results unveiled unexpected complications: the expected effect of line length was found only in neglect patients with frontal damage, while the expected effect of side of presentation was found only in neglect patients without frontal damage.

Stimulus context in hemineglect

Rightward deviation on bisection of a horizontal line is well described in patients with right brain injury and left hemineglect. Because of the observation that hemineglect patients may bisect very short lines to the left of the true midpoint (the so-called crossover effect), additional models have been proposed to incorporate this finding into existing theories of hemineglect. We investigated a line-length effect in six patients with left hemineglect. When presented with any set of lines of uniform (reference) length, percentage rightward deviation on line bisection remained constant across different line lengths. When lines of a second length were mixed into any uniform set of lines, bisection performance on the reference lines changed. A rightward shift in the perceived midpoint of the reference line occurred if the added lines were shorter than the reference lines; a leftward shift occurred if the added lines were longer. Leftward shifts included shifts across the true midpoint, reproducing the crossover effect. Shifts in the perceived midpoint occurred both on a manual line bisection task and on a line bisection discrimination task in which no manual response was required. We propose that the crossover effect may be part of a more general stimulus-context effect in which the perceived midpoint of a line is related not to absolute length, but to the line's length relative to other lines with which it is presented. Such a context effect has not hitherto been described in the neglect syndrome. A possible mechanism for the effect is a generalization of length estimation produced by the combined influence of the focal stimulus and all stimuli that precede it.

Improving precision for laser solid sampling for ICP emission with an array spectrometer.

An Excimer laser operating at the wavelength of 308 nm has been used to ablate soil for bulk analysis. The ablated material has been transferred to an array ICP emission spectrometer. In order to avoid a degraded reproducibility due to imhomogeneity, repetitive firings along a sampling line have been done at a firing frequency of 3 Hz. Effects of line length, read delay and internal standardization have been studied.

Differential Effects of Line Length on Bisection Judgements in Hemispatial Neglect

Recent studies have shown that certain symptoms of spatial neglect are co-determined by two major factors: one whose general nature is perceptual, the other whose nature is directional and/or motor. In the present study, Patients whose neglect was classified as predominantly ‘perceptual’ or ‘directional’ through use of the Landmark task (Milner, Brechmann and Pagliarini 1992) were asked to bisect lines ranging in length from 20 to only 2.5 cm. It was found that the one patient with predominantly directional neglect showed large rightward errors at all line lengths. In contrast, those with perceptual neglect made very small (usually leftward) errors on short lines. It is argued that it is essential to separate these different subtypes of neglect patient if we are to understand the causation of their behaviour in tasks such as line bisection.

The Output Process of Serial Production Lines of General Machines with Finite Buffers

Little is known about the interaction among manufacturing subsystems in a factory. The output of one manufacturing subsystem is usually the input to one or more others in the plant. For example, a production line may provide input to another manufacturing stage, a shipping system, or an automated parts conveyor. In all of these examples, the characteristics of the output from the production line can affect the subsequent process. This paper examines the output process of a serial production line of N machines with general processing time distributions and finite buffer capacities. Simulation is used to examine the effects of line length, buffer capacity, and buffer placement on the inter-departure distribution and correlation structure (autocorrelation function) of the output process of the production line. Results from this analysis are useful in setting production line design parameters and in determining the extent to which buffer placement can be used to control the variability of the output process, and thereby the amount of work-in-process present in downstream subsystems. Additional insights are provided to help explain why small buffers in production lines are normally adequate and to help us better understand the effects of buffers on tightly coupled production systems. By using a variety of processing time distributions, previously unknown effects attributed to skew of processing time are revealed. Since skew can often be reduced or eliminated by operator training, these effects are of particular interest since they can help to quantify some of the benefits of training.

The Output Processes of Serial Production Lines of Exponential Machines with Finite Buffers

Little is known about the interaction among the various manufacturing subsystems in a factory. The output of one manufacturing subsystem is usually the input to one or more downstream subsystems in the plant. Examples include the output of one production line being the input to another manufacturing stage, to a shipping system, or to an automated part conveyor. In all these examples, the output process of the production line forms the arrival process to the next subsystem. This paper develops a technique to analytically describe the output process of a serial production line of N machines with exponential processing time distributions and finite buffer capacities. Extensive exact results are used to examine the effects of line length, buffer capacity, and buffer placement on the interdeparture distribution, correlation structure, and variability of the output process of the production line. These results are used to determine the extent to which buffer allocation can be used to control the variability of the output process (and thereby the amount of work-in-process required to downstream subsystems). In addition, insights are provided to help explain why small buffers in production lines are normally adequate.

The measurement of dynamic differential pressúre with reference to the determination of pulsating flows using DP devices

Commercially available DP transmitters are generally unsuitable for dynamic measurements. The dynamic characteristics of a measurement system using a differential pressure transducer with transmission lines coupled to the pressure tapping points imposes particular constraints upon the measurements. The effects of both transmission line length and the use of liquids and gases upon the measurement system resonant frequencies and, hence, its dynamic performance are investigated. Practical aspects and calibration procedures are discussed.