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McManus et al. [2011] studied a user's ability to judge errors in self-produced motion; more specifically, throwing. We now take the first step towards discriminating what cues subjects are using in order to make their judgments. The endpoint of the ball is one such cue; the restricted field of view (FOV) of the head mounted display (HMD) makes it difficult for users to view the complete trajectory of the ball, making the endpoint one of the more consistent cues available during the experiment. For the current study, we hid the trajectory of the ball and showed only the landing point of the ball.

This paper describes a system for a new altitude measurement method, using three circular marks on the landing location for a Vertical Take-Off/Landing (VTOL) aircraft without an altimeter. This system costs less than a radar altimeter, yet it is more accurate than a pressure altimeter at low altitude and simpler than the Carrier Phase Differential Global Positioning System (CDGPS). The proposed method requires only an onboard camera, three circular marks placed on the landing site, and a control computer. The onboard camera must be facing toward the front of the aircraft and configured to detect the shape of the circular mark in image data form. The flight control computer calculates the altitude based on the known distance between the circular marks and the landing point. The accuracy of the proposed method is described in the analysis results section.

This paper addresses the investigation into the feasibility of the use of precision guided airdrop as a means to deliver cargo to naval vessels at sea. In this context, precision guided airdrop means delivering unmanned cargo packages that, once dropped from an aircraft at high altitude, have the capability to guide themselves to a precise landing point by con- trolling an aerodynamic decelerator (parafoil or parachute) to which the cargo package is attached. The paper describes the problem of replenishment of naval vessels at sea and describes the benefits that the application of precision airdrop might provide. Improved accuracy of aerial delivery systems is the major focus of analysis, and how the application of model predictive control has potential to achieve the necessary improvements in accuracy that would make shipboard landings possible. A simple example is developed of a model predictive control algorithm adapted to track a target landing area that is moving with constant velocity. Additional techniques are also surveyed, as well as other potential applications of precision airdrop to maritime operations.

Based on the analysis of the forces acting on the aircraft running on the runway with two opposite transverse gradients, this paper sets up the motion equation of the aircraft and puts forward the calculating method of side slippage. According to the laws of aircraft running on the runway and the data of transverse distribution of landing point, this paper further studies the minimum requirement for the width of the runway. The results indicate that the width of a runway for type A aircraft needs to be at least 50m generally. Under special conditions, the width should not be less than 25m. 3 figs, 6 refs.

Barrier coverage of a wireless sensor network aims at detecting intruders crossing the network. It provides a viable alternative for monitoring boundaries of battlefields, country borders, coastal lines, and perimeters of critical infrastructures. Early studies on barrier coverage typically assume that sensors are deployed uniformly at random in a large area. This assumption, while theoretically interesting, may be unrealistic in real applications. We take a more realistic approach in this paper. In particular, we consider that sensors are airdropped from an aircraft along its flying route. We note that wind, geographic terrain, and other factors may cause a sensor to land in a location deviating from its targeted landing point with a random offset. Thus, it is more realistic to assume that sensor nodes are distributed with a normal offset along the deployment line. Through extensive simulations, we study how variance of the normal distribution, the number of deployment lines, and the distance between adjacent lines would affect barrier coverage. We then investigate how a strong barrier can be formed efficiently from airdropped sensors and compare it with barrier coverage using uniformly distributed sensors. Our results show that the barrier coverage, with appropriately chosen deployment parameters, can be significantly improved using normally distributed sensors.

Summary Numerous animal navigators are not simply at the mercy of winds and currents but cope with drift to reach their goals [1–7]. Here, we report how a fruit-catching Costa Rican fish combines an analysis of aerial motion with a novel way of compensating for drift to optimize its catching success. In the field, schools of this riverine fish never waited until a falling fruit actually landed in the stream. Rather, the fish responded to visual motion and started early to arrive on time at the spot where their food would land. To be successful with their early starts, the fish must cope with the strong relative drift that arises, because the fish, but not their airborne target, experience strong flow on their way toward the fruit's landing point. Surprisingly, the fish solve this problem right at the beginning—by turning rapidly and taking an initial aim that is already optimally adapted to the prevailing drift, so as to lead them straight to their food. Fruit-catching fish thus provide a stunning case of how rapidly animals can generate drift-compensating trajectories in their everyday local lives.

*† ‡ § , Application of i nterval analysis is an innovative way of finding a guaranteed global optimu m. The main idea behind interval arithmetic is to use small intervals for the calculation instead of crisp numbers. As the interval algorithm has characteristics to check all numbers within the interval and contain s all feasible solutions, eventually a guaranteed global optimum can be found. This paper presents the results of a feasib ility study on how interval analysis can be applied to the non -linear re -entry -trajectory optimization problem of minim izing the heat load wh ile return ing to a desired landing point. To introduce the method two examples of static and dynamic optimization are presented first. Interval analysis applied to static optimization is very successful. Although the application to dynamic system s can su ccessfully give the global optimum, the method suffer s a lot from some intrinsic problems related to interval arithmetic, namely the so -called dependency problem, the wrapping effect and the huge number of feasible solutions returned from the algorithm . Th e re -entry trajectory optimization problem appeared to be very demanding for the applied algorithm .

In order to achieve safe and precise landings anywhere on the lunar surface without the heavy involvement of mission operations required during Apollo, an autonomous flight manager (AFM) is needed to assist the crew in managing the landing mission. An essential algorithm within the AFM is the landing point redesignation (LPR) function, which determines a prioritized list of safe and precise points in the landing region from which the crew can select a landing aimpoint. The LPR function described in this paper is flexible enough to support a variety of missions and situations by allowing an operator to reach-in and modify parameters prior to and throughout the landing.

The purpose of the study was to determine the mechanical variables that are related to successful post-flight somersaulting performance of the Roche vault. The 23 Roche vaults performed during the 2000 Olympic Games were filmed by a 16-mm camera operating at 100 Hz. The 2-D direct linear transformation technique was used for spatial calibration. Approximately 60 frames were digitized per vault. The method of Hay and Reid (1988) was used to develop a deterministic model to identify the mechanical variables that govern linear and angular motions of the vault. Correlational analysis was used to establish the strength of the relationship between the mechanical variables identified and the judges’ scores. Significant correlations indicated that the higher judges’ scores were negatively related to five mechanical variables and positively related to seventeen variables in the model. The normalized horizontal displacement of body center of mass (CM) from the knee grasp to the peak of post-flight was the best single predictor of the judges’ score and accounted for 50% of variation in the judges’ score. Finally, the landing point deductions and the official horizontal distance of post-flight collectively accounted for 86% of the variance in the judges’ scores.

This paper presents a review and summary of experimental findings on the role of attention in the preparation of saccadic eye movements. The focus is on experiments where performance of prosaccades (saccades towards a suddenly appearing item) and antisaccades (saccades of equal amplitude in the direction opposite to where the target moved) is compared. Evidence suggests that these two opposite responses to the same stimulus event entail competition between neural pathways that generate reflexive movements to the target and neural mechanisms involved in inhibiting the reflex and generating a voluntary gaze shift in the opposite direction to the target appearance. Evidence for such a competition account is discussed in light of a large amount of experimental findings and the overall picture clearly indicates that this competition account has great explanatory power when data on saccadic reaction times and error rates are compared for the two types of saccade. The role of attention is also discussed in particular in light of the finding that the withdrawal of attention by a secondary task 200 to 500 ms before the saccade target appears, leads to speeded antisaccades (without a similar increase in error rates), showing that the results do not simply reflect a speed-accuracy trade-off. This result indicates that the tendency for "reflexive" prosaccades is diminished when attention is engaged in a different task. Furthermore, experiments are discussed that show that as the tendency for a reflexive prosaccade is weakened, antisaccades are speeded up, further supporting the competition account of pro- and antisaccade generation. In the light of evidence from neurophysiology of monkeys and humans, a tentative model of pro- and antisaccade generation is proposed.

Many studies have found a strong coupling between selective attention and eye movements. The premotor theory of attention suggests that saccade preparation is directly responsible for such attentional shifts. While it has already been shown that the attentional shift is not directly coupled to the final stages of motor execution, it is currently unknown to what aspect of the earlier stages of saccade preparation the attentional shift is coupled. An important step in this preparation process is resolving the landing point when multiple elements compete for the saccade. Here we ask how such a competition influences the presaccadic attentional locus and whether the presaccadic shift of attention is coupled to the saccade landing position or the possible saccade goals. To this end, we adopt a global effect paradigm where a target is accompanied by a salient distractor resulting in the majority of eye movements landing in between target and distractor. To determine the allocation of attention, participants are presented with a discrimination task shortly before the execution of the saccade. Despite a strong global effect obtained for saccade endpoints, we find little evidence for attentional facilitation at the location between target and distractor, but strong attentional facilitation at the location of the target and distractor. We argue that attention is coupled to active oculomotor programs, but not part of the resolution of these programs towards the execution of the saccade.

Prior to an eye movement, attention is gradually shifted toward the point where the saccade will land. Our goal was to better understand the allocation of attention in an oculomotor capture paradigm for saccades that go straight to the eye movement target and for saccades that go to a distractor and are followed by corrective saccades to the target (i.e., involuntary saccades). We also sought to test facilitation at the future retinotopic location of target and nontarget objects, with the principal aim of verifying whether the remapping process accounts for the retinal displacement caused by involuntary saccades. Two experiments were run employing a dual-task design, primarily requiring participants to perform saccades toward a target while discriminating an asymmetric cross presented briefly before saccade onset. The results clearly show perceptual facilitation at the target location for goal-directed saccades and at the distractor location when oculomotor capture occurred. Facilitation was observed at a location relating to the remapping of a future saccade landing point, in sequences of oculomotor capture. In contrast, performance remained unaffected at the remapped location of a salient distracting object, which was not looked at. The findings are taken as evidence that presaccadic enhancement occurs prior to involuntary and voluntary saccades alike and that the remapping process also indiscriminatingly accounts for the retinal displacement caused by either.

The 385 kg Stardust mission was launched on Feb 7, 1999 on a mission to collect samples from the tail of comet Wild 2 and from interplanetary space. Stardust returned to Earth in the early morning of January 15, 2006. The sample return capsule landed in the Utah Test and Training Range (UTTR) southwest of Salt Lake City. Because Stardust was landing on Earth, hazard analysis was required by the National Aeronautics and Space Administration, UTTR, and the Stardust Project to ensure the safe return of the landing capsule along with the safety of people, ground assets, and aircraft. This paper focuses on the requirements affecting safe return of the capsule and safety of people on the ground by investigating parameters such as probability of impacting on UTTR, casualty expectation, and probability of casualty. This paper introduces the methods for the calculation of these requirements and shows how they affected mission planning, site selection, and mission operations. By analyzing these requirements before and during entry it allowed for the selection of a robust landing point that met all of the requirements during the actual landing event.

This paper describes the development of intelligent vision capabilities for small sized UAVs (Unmanned Aerial Vehicles) as part of the program “CAROLO”, currently underway at the Technische Universitat Braunschweig, Germany. The objective of this development is to create image processing algorithms and appropriate hardware that suites the requirements of small sized UAVs. Enabling vision-based flight guidance during landing was chosen as the first task and acts as a technology demonstrator for future vision capabilities. The characteristics of a laid out marker are extracted from the onboard imagery and relative position and attitude of this marker relative to the body-fixed coordinate system are determined. This concept conveys information about the designated landing point to the aircraft. An experimental installation was used for first measurements. This experiment and the results of the measurements in particular the attainable accuracies of the presented system are the subject of this publication.

The core of the presented GNC algorithm is the socalled ‘T-Approach’ that was developed by the Institute of Flight Systems of the German Aerospace Center (DLR). This guidance strategy, which works with waypoints that are continuously updated during the flight, enables the system to find its predefined landing point with a reasonable accuracy even in presence of turbulence, inaccuracies in wind or system parameters and typical sensor errors. In the past, many advanced features (e.g. on-board wind estimation, inclusion of geographical waypoints, etc.) have been worked out and implemented, in order to improve the flexibility, robustness, adaptability and accuracy of the GNC. The paper gives an overview about the working principles of the basic algorithm and the new extensions, discusses their advantages and possible drawbacks, and demonstrates the improvements by simulation and Monte-Carlo analysis. Abbreviations and Symbols

The international situation deteriorated as July progressed. The decision by Admiral Prince Louis of Battenberg, First Sea Lord, on 26 July 1914 to reinstitute what had been a test mobilization rather than the usual annual naval manoeuvres, meant that the fleet was at its war stations by 31 July. The War Office, too, was preparing for what seemed the inevitable and on 28 July ordered Special Service Sections of Territorial Force units to proceed to their Precautionary Period stations on the coast.1 Forty-five men of the 8/Essex patrolled the coast near Harwich and thirty men of the Northern Cyclist Battalion watched the Tyne estuary. When they arrived at their designated positions, cyclists of the 25/London discovered many of the coastguard stations near Rye were already deserted; their naval personnel had already gone to man the naval war signal stations or were still with the fleet for the test mobilization.2 The Special Service Section of the 4/Buffs moved to their positions at Thanet wireless station and the cable landing point at Dumpton Gap and 102 men of the 4/Duke of Wellingtons arrived at Grimsby docks.3 By 2 August, Ipswich wireless station was guarded by a section of the 1/Cambridgeshire and, by the same date, 120 men of the 7/Black Watch were already at their position in Kinghorn Fort. A much larger number of their comrades in the 5/Black Watch had been manning sections of the Tay defences since Tuesday 28 July.4

We give an overview of the tools to detect computer viruses without relying on “pattern files” that contain “signatures” of previously captured viruses. The system combines static code analysis with code simulation to identify malicious behaviors commonly found in computer viruses such as mass mailing, file infection, and registry overwrite. These prohibited behaviors are defined separately as security policies at the level of API library function calls in a state-transition like manner. The current tools target at Win32 binary viruses on Intel IA32 architectures and early experiments show that they can detect most email viruses that had spread in the wild in recent years.

This paper presents a full description of the design of a trot locomotion that has been implemented on AIBO quadrupeds in the Sony legged league. This work is inspired by the UNSW achievements in RoboCup 2000 and 2001 in Melbourne and Seattle. The French team rebuilt a complete trot locomotion from scratch, and introduced special features that differ from the Australian original design. Many papers have already been dedicated to the work on quadruped locomotion [2-4]. However they do not detail all the parts of the design.

Moments after a baseball batter has hit a fly ball, an outfielder has to decide whether to run forward or backward to catch the ball. Judging a fly ball is a difficult task, especially when the fielder is in the plane of the ball's trajectory. A previous study in experimental psychology suggests that to intercept the ball, the fielder has to run such that d/sup 2/(tan/spl phi/)/dt/sup 2/ is close to zero, where /spl phi/ is the elevation angle of the ball from the fielder's perspective. The authors investigate whether d/sup 2/(tan/spl phi/)/dt/sup 2/ information is sufficient to learn this task in two reinforcement learning models: AHC and Q learning. The authors' results indicate that although d/sup 2/(tan/spl phi/)/dt/sup 2/ provides initial clue as to the ball's landing point, it is not a good indicator in the latter stages of the ball's trajectory. Thus the two models fail to learn to intercept fly balls. However, when information about the perpendicular velocity of the ball with respect to the fielder is also included as an input to the system, it provides the necessary discriminability in the latter stages of the ball's trajectory, and the two models are able to successfully learn this reinforcement problem. >

The present paper presents a study of the optimal bidimensional entry into Earth atmosphere of a lifting vehicle with minimum heating. The variational problem is formulated as an izoperimetric problem 1, the imposed horizontal distance having a major signification in determination of the landing point. In this context, the variational optimal laws of the variation of the main motion parameters are inferred, the results obtained being applied to accomplish numerical applications of large practical interest.

International audience; This study investigated whether the execution of an accurate pointing response depends on a prior saccade orientation towards the target, independent of the vision of the limb. A comparison was made between the accuracy of sequential responses (in which the starting position of the hand is known and the eye centred on the target prior to the onset of the hand pointing movement) and synergetic responses (where both hand and gaze motions are simultaneously initiated on the basis of unique peripheral retinal information). The experiments were conducted in visual closed-loop (hand visible during the pointing movement) and in visual open-loop conditions (vision of hand interrupted as the hand started to move). The latter condition eliminated the possibility of a direct visual evaluation of the error between hand and target during pointing. Three main observations were derived from the present work: (a) the timing of coordinated eye-head-hand pointing at visual targets can be modified, depending on the executed task, without a deterioration in the accuracy of hand pointing; (b) mechanical constraints or instructions such as preventing eye, head or trunk motion, which limit the redundancy of degrees of freedom, lead to a decrease in accuracy; (c) the synergetic movement of eye, head and hand for pointing at a visible target is not trivially the superposition of eye and head shifts added to hand pointing. Indeed, the strategy of such a coordinated action can modify the kinematics of the head in order to make the movements of both head and hand terminate at approximately the same time. The main conclusion is that eye-head coordination is carried out optimally by a parallel processing in which both gaze and hand motor responses are initiated on the basis of a poorly defined retinal signal. The accuracy in hand pointing is not conditioned by head movement per se and does not depend on the relative timing of eye, head and hand movements (synergetic vs sequential responses). However, a decrease in the accuracy of hand pointing was observed in the synergetic condition, when target fixation was not stabilised before the target was extinguished. This suggests that when the orienting saccade reaches the target before hand movement onset, visual updating of the hand motor control signal may occur. A rapid processing of this final input allows a sharper redefinition of the hand landing point.

The word I see most often in connection with contemporary Japanese women's poetry is yureteiru, shaking. The poetry is not unstable and certainly not indifferent, just shaking-in flux and reaching for a landing point, however impermanent. This shaking is thrown into relief by the assumed stability of society as a whole. The Japanese economy is coming apart at the seams, but most people rarely speak of it. A startling common concept is isshin-denshin, essentially meaning "mind reading"-the ability of one Japanese person to see into another' s heart without an exchange of words. Also, I have had a highly educated older gentleman tell me calmly that no foreigners live in Japan, when he knew very well that I'd been living there for two years. There is a myth of homogeneity and definability. Social roles and perceptions are changing, but slowly. Even in the early 1990s, "understanding personal responsibility" and "self-reliance" ranked highest on a list of desirable qualities to develop in young boys, while the same qualities ranked low for girls. High-ranking female attributes were "sensitivity to other people's needs" and "gentleness." Just ten years ago, only 34 percent of Japanese people polled said that girls and boys should be raised the same, compared to 62 percent of Americans polled, 67 percent of Philippinos/Philippinas, and 92 percent of Swedish people.

were also within 100-200 m of the river. The species does not occur on the North Platte River bluEs south of the town of Saratoga or north from there for several km; in that area the bluffs are chalky and apparently unsuitable for the lizards. We here report collecting another example of the same subspecies (CUM 56045) on the bluffs near the landing point on the North Platte River 14.7 km NNEN of Sinclair, Wyoming, in Sect. 11, NE 1/4, T22N, R86W. The site is about 2.5 km by road from the locality reported by Morrison and Powell. Suitable habitat for the species occurs along the river some 10 km farther to the east, to Seminoe lleservoir, where the original habitat has been destroyed. It appears, therefore, that the East Slope population of S. u. elongatus is limited to the immediate vicinity of the North Platte River from about 15 km N of Saratoga to Seminoe Reservoir. It is separated by about 182 km from the nearest records of the West Slope populations (Morrison and Powell 1988:86). Having such a limited range, the East Slope population merits state and federal protection. The more southern individuals within that range are moderately abundant (we estimate 2-3/hectare), but northern ones appear to be very sparsely distributed. Isolated though this population appears to be from West Slope populations, we have observed no consistently distinctive characteristics indicative of subspecific differentiation.

How does a baseball player learn to judge a fly ball? An experienced outfielder, observing the initial stages of flight, can predict the landing point rapidly and accurately. In 1968, S. Chapman [Am. J. Phys. 3 6, 868 (1968)] proposed that an outfielder unconsciously uses trigonometry to determine the landing point. However, Chapman assumed incorrectly that the effects of aerodynamicdrag could be ignored. The trajectory of a baseball is shown to be affected significantly by air resistance, so that the specific trigonometric factor cited by Chapman cannot provide useful cues to the fielder. In evaluating potentially useful cues, we take note not only of aerodynamicdrag, but also of the specific neurophysiological processes used for the detection of distance and motion. This study shows that the angular acceleration of the fielder’s line of sight to the ball provides the strongest initial cue to the location of the eventual landing point. This suggests that the fielder’s vestibular system, responding to the acceleration of the fielder’s head as he observes the initial stages of flight, may play a key role in the judgment process.

This paper describes the re-entry control algorithm which provides the prescribed landing point of tae space vehicle entering the Earth's atmosphere at parabolic velocity. The two-dip re-entry scheme is considered and the three dimensional vehicle motion over the both dip portions is investigated. The digital computer algorithm simulation shows that rather high accuracy of the landing coordinates may be obtained even in case of a long distance between the first dip and landing points and in spite of the large-scale uncertaintes in the atmospheric density distribution. The paper develops further the results of /I-6/.

In this paper, the free falling installation of the large-size Artificial Steel Reef (ASR) will be discussed in order. Specifically, a prediction of its landing point on the sea floor, the force of the impact to evaluate the stress of the members of the ASR upon landing and an actual impact acceleration for evaluating impact force will be explored.

The exercise held at Brussels Airport was carried out by inexperienced personnel to highlight the most common errors and shortcomings of an existing disaster plan.INCIDENT COMMUNICATIONOnce an aircraft is known to be in trouble, all the nearby fire brigades are alerted by means of the unique call number 900 and move to take up their stand-by position close to the landing point. The Military Hospital is also alerted and sends out a liaison car, with a doctor among its occupants. This car joins the stand-by position. Once the aircraft has crashed, the fire engines rush to the site and all the major university hospitals and the Military Hospital are notified by the same 900-code number. Disaster teams arrive by road.This report is almost exclusively limited to aspects of rescue, triage, on-site stabilization, and evacuation of the casualties.

Applied forensic engineering in the field of accident reconstruction is often required to determine vehicle speeds in crash and collision cases. One type of automobile crash is that in which a car becomes airborne after being launched from an abrupt change of ground contour. This treatise covers an analysis of speed at launch based on measured distances from a launch surface to the landing point and on the slope of the launch surface. A refinement is introduced accounting for the effect of pitch motion of the vehicle to obtain a more accurate evaluation of speed.