Infinite Corridor Research Articles

Spatial structure of workplace and communication between colleagues: A study of E-mail exchange and spatial relatedness on the MIT campus

How does the spatial structure of work environments affect social interactions among workers? Building on prior studies of both physical and electronic communication networks, we present the results of a study conducted on the MIT campus using an anonymized dataset of e-mail communication to examine how spatial relatedness between faculty, staff, and researchers’ office locations impact E-mail communication between them. Our findings suggest that (a) people whose offices are closer to each other by walking are more likely to exchange E-mails, (b) on the campus as a whole, people who are more likely to walk past each other’s offices on the way to or from work are more likely to exchange E-mails, and (c) people who share access to similar eating venues around their offices are more likely to exchange E-mails. However, when controlling for unobserved relationships within departments and research units, a higher likelihood of physical encounters on the way to one’s office can reverse the effect of E-mail exchange, potentially substituting electronic communication for physical interactions with colleagues who are encountered more often. Further, the existence of social ties can be negatively affected by crowdedness, i.e., the chances of communication are reduced when encounters with each other’s offices occur in more crowded corridors. On the other hand, crowdedness at eating venues has a positive effect. E-mail exchange is also more likely if researchers are connected via indoor corridors along MIT’s renowned “infinite corridor” network than if the physical connection between them requires crossing an outdoor space. The key innovations presented in the paper include a novel approach to analyzing encounter probabilities during participant’s journey to work; estimation of potential crowdedness in building corridors; and a similarity estimation in amenity access for different workers. Our analysis suggests that these types of spatial relationships, which go beyond simple distance between workers’ offices, can affect E-mail communication between workers. The results provide limited evidence that spatial planning may be used strategically to encourage social, cultural, and economic exchange or knowledge-spillovers within buildings and campuses.

Refined central limit theorem and infinite density tail of the Lorentz gas from Lévy walk

We consider point particle that collides with a periodic array of hard-core elastic scatterers where the length of the free flights is unbounded due to infinitely long corridors between the scatterers (the infinite-horizon Lorentz gas, LG). The Bleher central limit theorem (CLT) states that the distribution of the particle displacement divided by is Gaussian in the limit of infinite time t. However this result, describing the bulk of the distribution, is not as powerful as in normal diffusion cases. The Gaussian peak fails to describe the displacement’s moments of order higher than two and gives only half of the true value of the dispersion. These demand the tail of the distribution which is formed by rare long flights along the corridors where the particle propagates much further than in typical diffusive displacements due to collisions with close scatterers. We derive the tail using a Lévy walk (LW) model of the LG, demonstrating extreme sensitivity to single flight event. The tail depends on whether between the steps the particle moves ballistically or jumps instantaneously and it obeys the single-big-jump principle i.e. large deviations are formed fully in only one step of the walk. The validity of the LW model in the LG’s description was proved recently in studying another deficiency of the CLT—the slow (logarithmic) convergence to the Gaussian peak hindering its observability. Using the LW model, it was proposed that rescaling the LG’s displacement by a Lambert function factor instead of provides a fast convergent observable CLT, which was confirmed by the LG simulations. Here we demonstrate that this result can be simplified giving ‘mixed CLT’ where the scaling factor combines normal and anomalous diffusions. This fits the previous observation that if infinite corridors are narrow then for long time the diffusion is normal. We conjecture that for observables determined by single flight events the LW results can be transferred to the LG.

Infinite horizon billiards: Transport at the border between Gauss and Lévy universality classes.

We consider transport in two billiard models, the infinite horizon Lorentz gas and the stadium channel, presenting analytical results for the spreading packet of particles. We first obtain the cumulative distribution function of traveling times between collisions, which exhibits nonanalytical behavior. Using a renewal assumption and the Lévy walk model, we obtain the particles' probability density. For the Lorentz gas, it shows a distinguished difference when compared with the known Gaussian propagator, as the latter is valid only for extremely long times. In particular, we show plumes of particles spreading along the infinite corridors, creating power-law tails of the density. We demonstrate the slow convergence rate via summation of independent and identically distributed random variables on the border between Lévy and Gauss laws. The renewal assumption works well for the Lorentz gas with intermediate-size scattering centers, but fails for the stadium channel due to strong temporal correlations. Our analytical results are supported with numerical samplings.

Measuring logarithmic corrections to normal diffusion in infinite-horizon billiards

We perform numerical measurements of the moments of the position of a tracer particle in a two-dimensional periodic billiard model (Lorentz gas) with infinite corridors. This model is known to exhibit a weak form of superdiffusion, in the sense that there is a logarithmic correction to the linear growth in time of the mean-squared displacement. We show numerically that this expected asymptotic behavior is easily overwhelmed by the subleading linear growth throughout the time range accessible to numerical simulations. We compare our simulations to analytical results for the variance of the anomalously rescaled limiting normal distributions.

Physical insight into superdiffusive dynamics of Sinai billiard through collision statistics

We report on distinct steady-motion dynamic regimes in chaotic Sinai billiard (SB). A numerical study on elastic reflections from the SB boundary (square wall of length L and circle obstacle of radius R) is carried out for different R / L . The research is based on the exploration of the generalized diffusion equation and on the analysis of wall-collision and the circle-collision distributions observed at late times. The asymptotes for the diffusion coefficient D R and the corresponding diffusion exponent z R are established for all geometries. The universal ( R-independent) diffusion with D 1 ∽ t 1 / 3 and z 1 = 1.5 replaces the ballistic motion regime ( z 0 = 1 ) attributed to square billiard ( R = 0 ). Geometrically, this superdiffusive regime is bounded by small radii 0 < R < R 1 ( R 1 / L = 2 4 ), when both diagonal and non-diagonal Bleher's corridors are open in the correspondent square lattice of Lorentz gas (LG) model. The relaxation dynamics observed is ensured by the universal diffusive propagation of the regular-type and the bouncing-ball-type orbits. Within the random walk scheme, this superdiffusive regime is due to the Lévy flights between the long-distant scatterers. With the increase in circle radius ( R 1 ⩽ R < R 2 , R 2 = L / 2 ), the diagonal corridor closes, but the arc-touching effects continue to bring the long-living bouncing-ball orbits back to the non-diagonal infinite corridors. This transient non-universal dynamics with 1.5 < z R < 2 , also associated with the trapping of regular orbits, seems to be characteristic of non-fully hyperbolic billiard systems. In SB with finite horizon ( R ⩾ R 2 ), all the principal corridors are closed and the interplay between square and circle boundaries generates the known chaotic dynamics, attributed to the fully hyperbolic systems. This is also observed through the normal Brownian diffusion ( z 2 = 2 ) and the Gaussian statistics, proved for both kinds of collisions.

Exposure to a rotating virtual environment during treadmill locomotion causes adaptation in heading direction

The objective of this study was to investigate the adaptive effects of variation in the direction of optic flow, experienced during linear treadmill walking, on modifying locomotor trajectory. Subjects (n=30) walked on a motorized linear treadmill at 4.0 km h(-1) for 24 min while viewing the interior of a 3D virtual scene projected on to a screen 1.5 m in front of them. The virtual scene depicted constant self-motion equivalent to either (1) walking around the perimeter of a room to one's left (Rotating Room group) or (2) walking down the center of a hallway (Infinite Corridor group). The scene was static for the first 4 min and then constant rate self-motion was simulated for the remaining 20 min. Before and after the treadmill locomotion adaptation period subjects performed five stepping trials. In each trial they marched in place to the beat of a metronome at 90 steps min(-1) for a total of 100 steps while blindfolded in a quiet room. The subject's final heading direction (deg) and final X (fore-aft, cm) and final Y (medio-lateral, cm) positions were measured for each trial. During the treadmill locomotion adaptation period subjects' 3D torso position was measured. We found that subjects in the Rotating Room group, as compared with the Infinite Hallway group: (1) showed significantly greater deviation during post-exposure testing in the heading direction and Y position opposite to the direction of optic flow experienced during treadmill walking; and (2) showed a significant monotonically increasing torso yaw angular rotation bias in the direction of optic flow during the treadmill adaptation exposure period. Subjects in both groups showed greater forward translation (in the +X direction) during the post-treadmill stepping task that differed significantly from their pre-exposure performance. Subjects in both groups reported no perceptual deviation in position during the stepping tasks. We infer that viewing simulated rotary self-motion during treadmill locomotion causes adaptive modification of sensorimotor integration in the control of position and trajectory during locomotion, which functionally reflects adaptive changes in the integration of visual, vestibular, and proprioceptive cues. Such an adaptation in the control of position and heading direction during locomotion, because of the congruence of sensory information, demonstrates the potential for adaptive transfer between sensorimotor systems and suggests a common neural site for processing and self-motion perception and concurrent adaptation in motor output.

New center of diversity

MEMS @ MIT is a newly created center that is intended to bring together a diverse group of microelectromechanical systems (MEMS) researchers at the Massachusetts Institute of Technology (MIT) Fig. 1Download : Download high-res image (221KB)Download : Download full-size imageFig. 1. MIT’s Killian Court, designed by architect William Welles Bosworth, showing the Great Dome under which runs the famous ‘Infinite Corridor’. and to provide an industrial interface to organizations that seek to interact with the center. Fig. 1. MIT’s Killian Court, designed by architect William Welles Bosworth, showing the Great Dome under which runs the famous ‘Infinite Corridor’. The MIT MEMS research program has been in existence for more than 20 years and has seen a steady growth in the number of researchers and faculty. Today, there are more than 20 faculty doing MEMS research at MIT, with approximately 120 students and staff who come from seven different academic departments. The annual contract research volume of this group is well in excess of $12 million. In creating this center, the faculty are recognizing the substantial value that arises from the coordination of activities, as well as the benefits of focused interactions with organizations that seek to commercialize the research.

Visual Perception of Optic Flow in the Left and in the Right Visual Hemifield

Recently we have found right visual hemifield (HF) superiority in detection of local texture optic flow discontinuity (H O Levashova and O V Levashov, 1996 Perception25 Supplement, 128). In the present work we investigated a possible difference between hemifields in the perception of global optic flow. The stimulus consisted of two large texture fields which moved across the screen to the left and to the right from a central vertical line. It gave the illusion of motion through an infinite corridor with high walls. The left or the right wall could be curvilinear (convex) while the other one was flat. In order to make the task more difficult the central vertical meridian of the screen was occluded by a black mask with a width of 5 deg. The task of the subject was to detect the curvilinear wall and press the ‘left’ or the ‘right’ key in accordance with target position. When the target was absent (in some presentations both the walls were flat) or when the subject could not detect it he/she had to press the third key. The distance from the screen was 57 cm. One experimental session consisted of 100 – 150 trials. All subjects showed a superiority of the right hemifield (the difference was significant, p&lt;0.05). The observed right-hemifield superiority in the detection of large texture flow could suggest that the left hemisphere has a certain dominance in visual perception of optic flow. This is in agreement with the hypothesis that the left hemisphere is more ‘phasic’ and the right hemisphere is more ‘tonic’ [O V Levashov, 1989 Computational Models of Sensory Systems (Moscow: VINITI) (in Russian)].

Mens et manus at work: The distributed library initiative at MIT

Most buildings at MIT are connected, and the long hallway which runs the length of the main complex is called the “infinite corridor.” This design was intentional when the Cambridge campus began construction along the banks of the Charles River basin in 1913. The purpose of interconnecting buildings, in contrast to the separate buildings of many campus quadrangles, is to promote conversation and interchange among students, faculty, and staff. This was viewed especially important for the cross‐fertilization of interdisciplinary studies. What does this have to do with the DLI? It is an early analog of the DLI purpose to nourish and encourage the quality of education and research for the entire MIT community. Within the Athena computing environment students often learn cooperatively. Through services such as Discuss, an online meeting facility, students can ask questions, continue dialogue, probe for new answers, and relax. The DLI provides the information layer of this learning environment and helps to build the electronic infinite corridor.