| 42471. |
- Katterle, M., et al.
(författare)
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A Heck-type coupling for the synthesis of novel bridged metallochlorin-fullerene C-60 dyads
- 2006
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1099-0690 .- 1434-193X. ; :2, s. 414-422
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Tidskriftsartikel (refereegranskat)abstract
- A short and convenient synthesis of metallochlorin-C-60 dyads based on a Heck-type hetero coupling at the 3(2) position of a chlorin is described. p-Bromobenzaldehyde was treated with Zn-metalated 13(2)-demethoxycarbonylmethylpheophorbide a, using a palladium acetate/LiCl catalyst mixture under phase-transfer conditions in DMF at 70 degrees C. The resulting asymmetric olefin was obtained in a high trans/cis ratio. The desired trans isomer was separated and subsequently transformed into a donor-acceptor dyad by a 1,3-dipolar cycloaddition to C-60 in the presence of sarcosine in refluxing toluene. The resulting dyads are expected to undergo efficient photoinduced electron transfer and can potentially be utilized in solar energy conversion devices. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).
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| 42472. |
- Katterle, M., et al.
(författare)
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An artificial supramolecular photosynthetic unit
- 2007
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 447:4-6, s. 284-288
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Tidskriftsartikel (refereegranskat)abstract
- A biomimetic light harvesting and energy conversion unit is constructed by a modular self-organization methodology. A self-assembled antenna aggregate mimics the supramolecular light-harvesting structures of phototrophic bacteria, and an embedded reaction center model acts both as an energy acceptor and a charge transfer dyad. This unit can be viewed as a conceptual approach to self-assembled supramolecular solar cells, utilizing bio-inspired materials as a starting point for advanced solar energy conversion units. (C) 2007 Elsevier B.V. All rights reserved.
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| 42473. |
- Katumba, Brian, et al.
(författare)
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Agile Development in Automotive Software Development: Challenges and Opportunities
- 2014
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Ingår i: Product-Focused Software Process Improvement, Lecture Notes in Computer Science. - Cham : Springer. - 9783319138343
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Konferensbidrag (refereegranskat)abstract
- In modern cars, most of the functionalities are controlled by software. The increased significance of software-based functionality has resulted in various challenges for automotive industry, which is slowly transitioning towards being a software centric industry. Challenges include the definition of key competencies, processes, methods, tools, and organization settings to accommodate combined development of software and hardware. Based on qualitative research, this paper aims at understanding the applicability of agile methods to automotive software development. Our explorative case study with one of the development sections at Volvo Car Cooperation identified challenges in their software development process related to process perception and reactive mode, multi-tasking and frequent task switching, individualism and lack of complete knowledge, as well as long communication chains and low cross-function mind set. Moreover it prepares a transition of software development at this multinational automotive company towards agile by relating agile principles and practices to automotive software process challenges.
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| 42474. |
- Katzourakis, D. I., et al.
(författare)
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Driver Steering Override for Lane-Keeping Aid Using Computer-Aided Engineering
- 2015
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Ingår i: IEEE/ASME Transactions on Mechatronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1083-4435 .- 1941-014X. ; 20:4, s. 1543-1552
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Tidskriftsartikel (refereegranskat)abstract
- The decreasing cost of radar and camera sensory technology has established advanced driver assistance systems (ADAS) to the standard equipment of modern vehicles. ADAS employ semi-autonomous interventions in longitudinal (e.g., adaptive cruise control, ACC) and lateral (e.g., lane-keeping aid, LKA) direction. ACC and LKA constitute the milestones of ADAS technology and have shown to correspondingly reduce driving effort and unintended lane-drifts. ADAS and driver share the vehicle control; this in-turn creates a nonfinite number of test cases that have to be tested-verified so-as to enable safe software (SW) release. Adjacent to ADAS, vehicle dynamics-related systems, such as the antilock braking system and the dynamic-stability and traction control, have also to undergo through an exhaustive SW verification. Distilling the previous statements, this paper cultivates the concept of virtual SW verification by evaluating Volvo's production and a concept driver steering override (DSO) for LKA systems. The DSO concept addresses the driver's interaction with the LKA system and adapts the intervention level. The driver's activation is quantified though the steering torque and road/vehicle information. Two different test-runs per DSO strategy are presented and the real-car (physical) testing results are reproduced in simulation. Both the real and postprocessed simulation results show: 1) the importance of the override strategy on the LKA benefits; and 2) the importance of computer-aided engineering for studying/designing ADAS.
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| 42475. |
- Katzourakis, Diomidis, et al.
(författare)
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Vehicle steering arrangement, autonomous vehicle steering arrangement, a vehicle, and a method of steering a vehicle
- 2018
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- A vehicle steering arrangement for a vehicle comprises a rack a position sensor, a steering column, a steering wheel, a torque sensor arranged to sense a torque applied onto the steering wheel and arranged to provide a torque signal representative thereof, an electronic control unit provided with a virtual steering model, a rack-mounted electromechanical actuator, and a force obtaining arrangement configured to obtain forces of steered wheels acting on the rack. The electronic control unit is configured to provide a virtual rack position based on the virtual steering model and at least a combination of the obtained forces and the torque signal, and is arranged to control the rack-mounted electromechanical actuator such that the current position of the rack is controlled towards the virtual rack position. The present disclosure also relates to an autonomous vehicle steering arrangement, a vehicle and a method of steering a vehicle.
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| 42476. |
- Kaufman, M., et al.
(författare)
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CO observations of the interacting galaxy pair NGC 5394/95
- 2002
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 123:2 1754, s. 702-719
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Tidskriftsartikel (refereegranskat)abstract
- BIMA 12CO J = 1 → 0 observations are presented of the spiral galaxies NGC 5394 and NGC 5395 that have undergone a recent, grazing encounter. In NGC 5394 approximately 80% of the CO emission detected by BIMA is concentrated in the central 800 pc (FWHM) starburst region, and the rest is from a portion of the inner disk south and west of the central starburst. In an encounter simulation that reproduces some of the main features of this galaxy pair, a considerable amount of gas in NGC 5394 falls into the central region early in the collision. The observed total gas distribution in the disk of NGC 5394 is lopsided, with more H I, CO, and Hα emission coming from the western or southwestern side. The innermost western arm of NGC 5394 is seen in CO and Hα emission, but the eastern inner-disk arm, which is very bright in the optical continuum, is not detected in CO or Hα emission. The NGC 5394 starburst region is similar in radio continuum luminosity and size to the M82 starburst and has a CO luminosity ∼4 times greater. A CO position-velocity diagram of the NGC 5394 nucleus reveals two separate velocity features very close to the center. This may indicate a nuclear ring or the "twin peaks" of an ILR or some depletion of 12CO J = 1 → 0 at the nucleus. From a comparison of the radio continuum, Hα, 60 μm, and CO luminosities, we estimate that the average extinction A v of the starburst nucleus is 3-4 mag, the star formation rate is ∼6 M⊙ yr-1, and the conversion factor N(H 2)/ICO in the starburst is a factor of 3-4 below the standard value. Comparison of NGC 5394 with two other systems previously studied suggests that in prograde grazing encounters a central starburst may not develop until near the end of the ocular phase. Very little of the CO emission from NGC 5395 found in previous single-dish observations is detected in the BIMA data; thus molecular gas in NGC 5395 does not appear to be strongly concentrated in compressed ridges.
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| 42477. |
- Kaufman, M., et al.
(författare)
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Observations of the Ocular Galaxy NGC 2535 and its Starburst Companion NGC 2536
- 1997
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 114, s. 2323-2349
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Tidskriftsartikel (refereegranskat)abstract
- H I, radio continuum, and 12CO J=1-->0 observations at resolutions of 12" to 33" (=2.9-8 kpc), and B, I, J, and K-band images, are presented of the galaxy NGC 2535 and its small starburst companion NGC 2536. NGC 2535 has an ocular (eye-shaped) structure with two long tidal arms indicative of a recent, close, nonmerging encounter. Our observations reveal widespread high velocity dispersions (30 km s-1) in the H I gas and five clouds with masses of ˜10^8 Msun in the tidal arms of NGC 2535. These clouds do not correspond to the most luminous blue knots or to major clumps in the old stellar population. Similar phenomena were found previously in other pairs (IC 2163/NGC 2207 and NGC 5774/5), suggesting that enhanced turbulence and massive gas clouds may be a general feature of interacting spiral galaxies during an early phase of post-encounter evolution. A search for 12CO J= 1-->O emission at 11 positions in NGC 2535 and one position in NGC 2536 yielded two clear detections, one at the center of NGC 2535 and the other on its tidal tail but close to the center of NGC 2535. Most of the massive H I clouds in NGC 2535 are not detected in CO emission. The virial masses of these clouds are significantly greater than their measured masses in gas, presumably because of the presence of old disk stars in the clouds. A form of the virial theorem that includes gas and stars is presented. NGC 2535 shows several unusual features, including an intrinsically oval shape to the disk, that are similar to those in the ocular galaxy IC 2163 studied previously. NGC 2535 also contains structures that are not seen in IC 2163. For example, there is an extended (R =48 kpc) H I envelope and a long, outer, elliptically-shaped H I arc in NGC 2535 that may be a gravitational wake produced by the passage of the companion within or close to the envelope. In the radio continuum, NGC 2535 exhibits a bar-like feature that leads the small stellar bar by 50°. The starburst companion, NGC 2536, lies in a 2 X 10^9 Msun clump of H I gas at the outer end of the tidal bridge from NGC 2535. Most of the gas in this clump is associated with the bridge. The H I emission on the anticompanion side of NGC 2536 has the same line-of-sight velocity and projected position as some of the bridge gas there. This observation is consistent with a previous model by Klaric in which NGC 2536 accretes gas from NGC 2535; we even find an H I feature that may represent bridge gas streaming towards NGC 2536. The failure to detect 12CO emission in NGC 2536 places an upper limit of 6 X H2 on its H2 mass if the standard value of the conversion factor between I_CO and N(H2) applies.
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| 42478. |
- Kaufman, M., et al.
(författare)
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The Interacting Galaxies NGC 5394/5395: A Post-Ocular Galaxy and Its Ring/Spiral Companion
- 1999
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 118:4, s. 1577-1608
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Tidskriftsartikel (refereegranskat)abstract
- H I, radio continuum, Fabry-Perot Hα, and 12CO J = 1 → 0 observations and broadband optical and near infrared images are presented of the interacting spiral galaxies NGC 5395 and NGC 5394. Kinematically, there are three important, separate components to the H I gas associated with this galaxy pair: (1) the main disk of NGC 5395, (2) a long, northern tidal arm of NGC 5395 distinct in velocity from its main disk, and (3) the disk of NGC 5394. The H I northern tidal arm of NGC 5395 has a line of–sight velocity as much as 75–100 km s-1 greater than the main disk of NGC 5395 at the same projected location and thus is not in the same plane as the disk. The velocity field of the disk of NGC 5395 is asymmetric and distorted by large-scale and small-scale noncircular motions. In NGC 5395, the encounter appears to be exciting m = 1 and m = 0 modes in what had been a two-armed spiral. The dominant spiral arm of NGC 5395 forms a large ring or pseudo-ring of Hα, radio continuum, and H I emission, somewhat off center with respect to the nucleus. The H I trough in the center of NGC 5395 is not filled in by molecular gas. The Hα velocity contours exhibit an organized pattern of kinks in crossing the ring and also show streaming motions in a large stellar caustic feature. The eastern side of the ring is brighter in radio continuum and Hα; the western side is brighter in H I and contains massive (108 M☉) H I clouds not associated with the most luminous H II regions. The smaller galaxy NGC 5394 is in an immediate post-ocular phase, with a central starburst, an intrinsically oval disk, two long, fairly symmetric, open tidal arms with high arm-interarm contrast, and very bright inner spiral arms, disjoint from the outer tidal arms. Most of the gas in NGC 5394 is in molecular form and concentrated within 3.8 kpc of the center, so is suitable for fueling the starburst. Despite the presence of H I gas, two of the three optically bright inner spiral arms of NGC 5394 show no evidence of ongoing star formation.A galaxy encounter simulation reproduces some of the main features of this system with a collision that is prograde relative to NGC 5394 and retrograde at a high tilt angle relative to NGC 5395. The model finds that the inner spiral structure of NGC 5394 developed from an eye-shaped ("ocular") structure at slightly earlier times. NGC 5394 and the two ocular galaxies IC 2163 and NGC 2535, studied earlier, form an evolutionary sequence of structures resulting from prograde encounters and thus confirm the generic models of such collisions. The agreement between the model for NGC 5394/95 and the ring/spiral structures seen in NGC 5395 extends our understanding of collisional ring galaxies.
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| 42479. |
- Kaufmann, Lucas, 1988
(författare)
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A Skoda-type Integrability theorem for singular Monge-Ampère measures
- 2017
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Ingår i: Michigan Mathematical Journal. - : Michigan Mathematical Journal. - 0026-2285 .- 1945-2365. ; 66, s. 581-594
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Tidskriftsartikel (refereegranskat)abstract
- Let φ be a plurisubharmonic function defined on an open subset of Cn. We give a sufficient condition for the local integrability of e -φ with respect to a Monge-Ampère measure with Höldercontinuous potential μ = (ddcu)n. This condition is expressed in terms of the Lelong numbers of φ and the Hölder exponent of u.
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| 42480. |
- Kaufmann Sacchetto, Lucas, 1988, et al.
(författare)
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Density and intersection of (1,1)-currents
- 2019
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Ingår i: Journal of Functional Analysis. - : Elsevier BV. - 0022-1236 .- 1096-0783. ; 277:2, s. 392-417
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Tidskriftsartikel (refereegranskat)abstract
- We study density currents associated with a collection of positive closed (1,1)-currents on a complex manifold. We prove that the density current is unique and determined by the usual wedge product in some classical situations including the case where the currents have bounded potentials. As an application, we compare density currents with the non-pluripolar product and the Andersson-Wulcan product. We also analyse some situations where the wedge product is not well-defined but the density can be explicitly computed.
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