Space shuttle electromagnetic environment experiment. Phase A: Definition study

Methods for carrying out measurements of earth electromagnetic environment using the space shuttle as a measurement system platform are herein reported. The goal is to provide means for mapping intentional and nonintentional emitters on earth in the frequency range 0.4 to 40 GHz. A survey was made of known emitters using available data from national and international regulatory agencies, and from industry sources. The spatial distribution of sources, power levels, frequencies, degree of frequency re-use, etc., found in the survey, are here presented. A concept is developed for scanning the earth using a directive antenna whose beam is made to rotate at a fixed angle relative to the nadir; the illuminated area swept by the beam is of the form of cycloidal annulus over a sphere. During the beam's sojourn over a point, the receiver sweeps in frequency over ranges in the order of octave width using sweeping filter bandwidths sufficient to give stable readings

Venus cusp observations during 1969 - Synopsis of results

Venus cusp observations during 196

Stellenwert der endoskopischen Axilladissektion beim invasiven Mammakarzinom

Zusammenfassung: Grundlagen: Die Axilladissektion liefert zuverlässige prognostische Information, bestimmt mehrheitlich die adjuvante Therapie und reduziert die axillären Tumorrezidive. Die Morbidität nach Axilladissektion kann jedoch nicht vernachlässigt werden (sensible Störungen, Schmerzen, motorische Schwäche, Lymphödem). Patientinnen mit kleinen Tumoren (pT1a, b, c) könnten von neueren weniger invasiven Verfahren (endoskopische Axilladissektion) oder von selektiveren Methoden (Sentinel-lymph-node-Procedere) profitieren. In dieser prospektiven Studie wurde die axilloskopische Lymphadenektomie evaluiert. Methodik: 55 klinisch nodal negative Patientinnen (Durchschnittsalter: 60 Jahre [30 bis 86 Jahre]) wurden von einem Chirurgen endoskopisch operiert (Januar 1996 bis Juni 1998). Nach Liposuktion des axillären Fettkörpers wurden die Lymphknoten von Level I+II identifiziert und unter direkter endoskopischer Sicht reseziert (erfolgreiches Verfahren in 95 %: n=52). Die Patientinnen wurden entsprechend dem Nachsorgeschema alle 4 Monate kontrolliert. Nach einer mittleren Beobachtungszeit von 22 Monaten (7 bis 37 Monate; n=51 [eine Patientin verweigerte die Nachsorge]) wurden die Patientinnen mit einem Evaluationsfragebogen, einem Interview und einer klinischen Untersuchung (inklusiv Schultergelenksfunktion, Zirkumferenzmessungen der oberen Extremität) nachkontrolliert. Ergebnisse: Durchschnittlich wurden 13,3 (5 bis 25) Lymphknoten endoskopisch entfernt. Nodal positive Lymphknoten wurden in 31 % (n=16) beobachtet. Der Durchschnittswert der positiven Lymphknoten/Patientin betrug 3,1 (1 bis 10). Acht Serome (15 %) mußten in der frühpostoperativen Phase punktiert werden. Es traten keine Hämatome, jedoch ein Infekt in der Axilla nach Chemotherapie auf (2 %). Nach einer mittleren Beobachtungszeit von 22 Monaten (7 bis 37 Monate) konnten keine axillären Rezidive nachgewiesen werden. Eine subkutane Implantationsmetastase in der Narbe eines Trokarkanals (1/55, 2 %) wurde diagnostiziert und reseziert. Klinisch traten keine Lymphödeme auf. Die frühe Mobilisation des Schultergelenkes war subjektiv und objektiv gut. Schlußfolgerungen: Die durchschnittlich 13 axilloskopisch entfernten Lymphknoten entsprechen der Anzahl resezierter Lymphknoten bei offener Axilladissektion. Die Morbidität dieses in Evaluation begriffenen Verfahrens ist niedrig. Nach einer mittleren Beobachtungszeit von 22 Monaten wurde ein Implantationsrezidiv im subkutanen Kanal des anterioren Arbeitstrokar nachgewiesen. Eine längere Beobachtungszeit ist nötig, um die Technik empfehlen zu können. Es zeichnet sich ab, daß die endoskopische, axilläre Lymphknotendissektion durch das selektivere Sentinel-lymph-node-Verfahren abgelöst wir

Space shuttle electromagnetic environment experiment. Phase A: Definition study

A program is discussed which develops a concept for measuring the electromagnetic environment on earth with equipment on board an orbiting space shuttle. Earlier work on spaceborne measuring experiments is reviewed, and emissions to be expected are estimated using, in part, previously gathered data. General relations among system parameters are presented, followed by a proposal on spatial and frequency scanning concepts. The methods proposed include a nadir looking measurement with small lateral scan and a circularly scanned measurement looking tangent to the earth's surface at the horizon. Antenna requirements are given, assuming frequency coverage from 400 MHz to 40 GHz. For the low frequency range, 400-1000 MHz, a processed, thinned array is proposed which will be more fully analyzed in the next phase of the program. Preliminary hardware and data processing requirements are presented

Asymptotic information leakage under one-try attacks

We study the asymptotic behaviour of (a) information leakage and (b) adversary’s error probability in information hiding systems modelled as noisy channels. Specifically, we assume the attacker can make a single guess after observing n independent executions of the system, throughout which the secret information is kept fixed. We show that the asymptotic behaviour of quantities (a) and (b) can be determined in a simple way from the channel matrix. Moreover, simple and tight bounds on them as functions of n show that the convergence is exponential. We also discuss feasible methods to evaluate the rate of convergence. Our results cover both the Bayesian case, where a prior probability distribution on the secrets is assumed known to the attacker, and the maximum-likelihood case, where the attacker does not know such distribution. In the Bayesian case, we identify the distributions that maximize the leakage. We consider both the min-entropy setting studied by Smith and the additive form recently proposed by Braun et al., and show the two forms do agree asymptotically. Next, we extend these results to a more sophisticated eavesdropping scenario, where the attacker can perform a (noisy) observation at each state of the computation and the systems are modelled as hidden Markov models

Performance of Solar-Assisted Modified-Open-Front Swine Nurseries

Performance data of two modified-open-front non-mechanically ventilated swine nurseries have shown that solar energy can be effectively utilized to maintain a productive environment within the animal space during cold weather (temperatures as low as -26°C ( - 15 °F). The nurseries feature a monoslope roof design and passive collector panels that also function as warm weather ventilation panels. An active solar-heating system uses a ground-level collector operated in conjunction with an in-floor solar heat distribution and storage system. The nurseries were designed to handle pigs weighing from 7 to 23 kg (15 to 50 lb). An average of 19% of the solar energy incident on the collector was transferred to the floor surface during the heating seasons from October 1980 to January 1982. Season heating costs were approximately 1.0% of the estimated cost to heat the nursery by conventional means

DYNAMIC ROPS TEST FOR TRACTORS OVER 6,000 KILOGRAMS

OECD static tests (Codes 4, 6, 7, and 8) for agricultural rollover protective structures (ROPS) have become accepted standards for evaluating the ability of these structures to protect the operator during tractor rollover events. The strength properties of some materials typically used in ROPS change because of cold weather embrittlement at low temperatures. The static ROPS tests lack the ability to evaluate the strength of these structures during cold weather. The use of the dynamic ROPS test is well noted as a means for proving cold weather embrittlement resistance properties. Unfortunately, application of the OECD dynamic ROPS test (Code 3) is restricted to tractors with unballasted mass greater than 600 kg and generally less than 6,000 kg. The analyses presented in this technical note were undertaken to evaluate the extension of the OECD Code 3 dynamic ROPS test to tractors with unballasted mass of 6,000 kg or more. Tractor unballasted mass and wheelbase data from 47 wheeled tractors tested at the Nebraska Tractor Test Lab from 2014 to 2016 were used to explore the possibility of using a dynamic test method for evaluating the ability of ROPS on tractors with unballasted mass greater than 6,000 kg to meet the safety requirements of agricultural tractor ROPS. The data were graphed and analyzed to determine the required pendulum drop height and energy values to be applied to the ROPS by extending the existing equations to tractors over 6,000 kg. For tractors over 6,000 kg mass, it was determined that pendulum drop heights were too great for practical use. Three pendulum masses were proposed for the dynamic ROPS test: a 2,000 kg pendulum for tractors with mass less than 7,000 kg, a 4,000 kg pendulum for tractors with mass of 7,000 kg or more and less than 14,000 kg, and a 6,000 kg pendulum for tractors with mass of 14,000 kg or more and less than 23,000 kg. Alternate equations were developed for the drop height of each pendulum to meet the energy requirements that are expected to provide similar permanent deflections as those obtained when using the static ROPS test when considering the effect of strain rates on material properties. Tests should be conducted to determine how the results (permanent deflections) from the proposed dynamic ROPS test compare with results from the accepted static ROPS tests. It is further proposed that dynamic testing be conducted with the tractor rigidly restrained in a manner similar to the static test to better account for the wide variety of available tires and mountings for each tractor model

Using a vision sensor system for performance testing of satellite-based tractor auto-guidance

A vision sensing system for the measurement of auto-guidance pass-to-pass and long-term errors was implemented to test the steering performance of tractors equipped with auto-guidance systems. The developed test system consisted of an optical machine vision sensor rigidly mounted on the rear of the tested tractor. The center of the drawbar hitch pin point was used as the reference from which to measure the deviation of the tractor’s actual travel path from its desired path. The system was built and calibrated to a measurement accuracy of better than 2 mm. To evaluate the sensor, two auto-guidance systems equipped with RTK-level GNSS receivers were tested and the results for different travel speeds compared. Pass-to-pass and long-term errors were calculated using the relative positions of a reference at a collocated point when the tractor was operated in opposite directions within 15 min and more than 1 h apart, respectively. In addition to variations in speed, two different auto-guidance steering stabilization distances allowed for comparison of two different definitions of steady-state operation of the system. For the analysis, non-parametric cumulative distributions were generated to determine error values that corresponded to 95% of the cumulative distribution. Both auto-guidance systems provided 95% cumulative error estimates comparable to 51 mm (2 in.) claims and even smaller during Test A. Higher travel speeds (especially 5.0 m/s) significantly increased measured auto-guidance error, but no significant difference was observed between pass-to-pass and long-term error estimates. The vision sensor testing system could be used as a means to implement the auto-guidance test standard under development by the International Standard Organization (ISO). Third-party evaluation of auto-guidance performance will increase consumer awareness of the potential performance of products provided by a variety of vendors

Using a vision sensor system for performance testing of satellite-based tractor auto-guidance

A vision sensing system for the measurement of auto-guidance pass-to-pass and long-term errors was implemented to test the steering performance of tractors equipped with auto-guidance systems. The developed test system consisted of an optical machine vision sensor rigidly mounted on the rear of the tested tractor. The center of the drawbar hitch pin point was used as the reference from which to measure the deviation of the tractor’s actual travel path from its desired path. The system was built and calibrated to a measurement accuracy of better than 2 mm. To evaluate the sensor, two auto-guidance systems equipped with RTK-level GNSS receivers were tested and the results for different travel speeds compared. Pass-to-pass and long-term errors were calculated using the relative positions of a reference at a collocated point when the tractor was operated in opposite directions within 15 min and more than 1 h apart, respectively. In addition to variations in speed, two different auto-guidance steering stabilization distances allowed for comparison of two different definitions of steady-state operation of the system. For the analysis, non-parametric cumulative distributions were generated to determine error values that corresponded to 95% of the cumulative distribution. Both auto-guidance systems provided 95% cumulative error estimates comparable to 51 mm (2 in.) claims and even smaller during Test A. Higher travel speeds (especially 5.0 m/s) significantly increased measured auto-guidance error, but no significant difference was observed between pass-to-pass and long-term error estimates. The vision sensor testing system could be used as a means to implement the auto-guidance test standard under development by the International Standard Organization (ISO). Third-party evaluation of auto-guidance performance will increase consumer awareness of the potential performance of products provided by a variety of vendors