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  • Kaartinen, Harri; Hyyppä, Juha; Vastaranta, Mikko; Kukko, Antero; Jaakkola, Anttoni; Yu, Xiaowei; Pyörälä, Jiri; Liang, Xinlian; Liu, Jingbin; Wang, Yungshen; Kaijaluoto, Risto; Melkas, Timo; Holopainen, Markus; Hyyppä, Hannu (MDPI, 2015)
    A harvester enables detailed roundwood data to be collected during harvesting operations by means of the measurement apparatus integrated into its felling head. These data can be used to improve the efficiency of wood procurement and also replace some of the field measurements, and thus provide both less costly and more detailed ground truth for remote sensing based forest inventories. However, the positional accuracy of harvester-collected tree data is not sufficient currently to match the accuracy per individual trees achieved with remote sensing data. The aim in the present study was to test the accuracy of various instruments utilizing global satellite navigation systems (GNSS) in motion under forest canopies of varying densities to enable us to get an understanding of the current state-of-the-art in GNSS-based positioning under forest canopies. Tests were conducted using several different combinations of GNSS and inertial measurement unit (IMU) mounted on an all-terrain vehicle (ATV) simulating a moving harvester. The positions of 224 trees along the driving route were measured using a total-station and real-time kinematic GPS. These trees were used as reference items. The position of the ATV was obtained using GNSS and IMU with an accuracy of 0.7 m (root mean squared error (RMSE) for 2D positions). For the single-frequency GNSS receivers, the RMSE of real-time 2D GNSS positions was 4.2-9.3 m. Based on these results, it seems that the accuracy of novel single-frequency GNSS devices is not so dependent on forest conditions, whereas the performance of the tested geodetic dual-frequency receiver is very sensitive to the visibility of the satellites. When post-processing can be applied, especially when combined with IMU data, the improvement in the accuracy of the dual-frequency receiver was significant.
  • Enroth, Johannes; Olsson, Sanna; Long, David G.; Quandt, Dietmar (2012)
    Pinnatella gollanii Broth., previously known only from north Indian collections dating back to 1903, was rediscovered in Nepal in 2001.
  • Metsälä, M; Schmidt, F; Skyttä, M; Vaittinen, O; Halonen, L (IOP Publishing, 2010)
  • Dixon, Helen Marie (Routledge - Taylor & Francis Group, 2015)
  • Watanabe, Kazuho; Roos, Teemu; Myllymäki, Petri (2013)
    Journal of Machine Learning Research: Workshop and Conference Proceedings
    The normalized maximum likelihood model achieves the minimax coding (log-loss) regret for data of fixed sample size n. However, it is a batch strategy, i.e., it requires that n be known in advance. Furthermore, it is computationally infeasible for most statistical models, and several computationally feasible alternative strategies have been devised. We characterize the achievability of asymptotic minimaxity by batch strategies (i.e., strategies that depend on n) as well as online strategies (i.e., strategies independent of n). On one hand, we conjecture that for a large class of models, no online strategy can be asymptotically minimax. We prove that this holds under a slightly stronger definition of asymptotic minimaxity. Our numerical experiments support the conjecture about non-achievability by so called last-step minimax algorithms, which are independent of n. On the other hand, we show that in the multinomial model, a Bayes mixture defined by the conjugate Dirichlet prior with a simple dependency on n achieves asymptotic minimaxity for all sequences, thus providing a simpler asymptotic minimax strategy compared to earlier work by Xie and Barron. The numerical results also demonstrate superior finite-sample behavior by a number of novel batch and online algorithms.
  • Lambert, David; Solem, Michael; Tani, Sirpa (Routledge, 2015)
    This article provides the theoretical underpinnings for an innovative international collaborative project in the field of geography education named GeoCapabilities. The project attempts to respond in new ways to enduring challenges facing geography teachers in schools. These include the need to find convincing expression of geography's contribution to the education of all young people and coping with the apparent divergence of geography in educational settings and its highly disparate expression as a research discipline in university departments. The project also hopes to contribute to the development of a framework for communicating the aims and purposes of geography in schools internationally, because here, too, there is great variety in definitions of national standards and even of disciplinary allegiances (including, e.g., the social studies, humanities, and biological sciences). GeoCapabilities does not seek to flatten such divergences, for one of geography's great strengths is its breadth. The long-term goal is to establish a secure platform for the international development of teachers' capacities as creative and disciplined innovators. The project encourages teachers to think beyond program delivery and implementation and to embrace their role as the curriculum makers.
  • Konttinen, Y T; Mandelin, J; Li, T F; Salo, J; Lassus, J; Liljestrom, M; Hukkanen, M; Takagi, M; Virtanen, I; Santavirta, S (JOHN/WILEY & SONS, INC, 2002)
  • Alcamo, J.; Amann, M; Hettelingh, J.-P.; Holmberg, M.; Hordijk, L.; Kämäri, J.; Kauppi, L.; Kauppi, P.; Kornai, G.; Mäkelä, A. (Royal Swedish Academy of Sciences, 1987)
  • Kauppi, P.E.; Kämäri, J.; Posch, M.; Kauppi, L.; Matzner, E. (Elsevier, 1986)
  • Alcamo, J.; Kauppi, P.E.; Posch, M.; Runca, E. (IIASA, 1984)
  • Leinonen, Jussi; Moisseev, Dmitri; Leskinen, Matti; Petersen, Walter A. (American Meteorological Society, 2012)
    To improve the understanding of high-latitude rain microphysics and its implications for the remote sensing of rainfall by ground-based and spaceborne radars, raindrop size measurements have been analyzed that were collected over five years with a Joss–Waldvogel disdrometer located in Järvenpää, Finland. The analysis shows that the regional climate is characterized by light rain and small drop size with narrow size distributions and that the mutual relations of drop size distribution parameters differ from those reported at lower latitudes. Radar parameters computed from the distributions demonstrate that the high latitudes are a challenging target for weather radar observations, particularly those employing polarimetric and dual-frequency techniques. Nevertheless, the findings imply that polarimetric ground radars can produce reliable “ground truth” estimates for space observations and identify dual-frequency radars utilizing a W-band channel as promising tools for observing rainfall in the high-latitude climate.
  • Weiste, Elina; Peräkylä, Anssi (Routledge, 2013)
    46(4), 299–321, 2013
  • Kant, Ravi; Kerminen (née Rintahaka), Johanna; Yu, Xia; Sigvart-Mattila, Pia; Paulin, Lars; Mecklin, Jukka-Pekka; Saarela, Maria; Palva, Airi; von Ossowski, Ingemar (PUBLIC LIBRARY OF SCIENCE, 2014)
  • Eronen, J. T.; Micheels, A.; Utescher, T. (EVOLUTIONARY ECOLOGY LTD, 2011)
  • Clark, Christine; Palta, Priit; Joyce, Christopher J.; Scott, Carol; Grundberg, Elin; Deloukas, Panos; Palotie, Aarno; Coffey, Alison J. (PUBLIC LIBRARY OF SCIENCE, 2012)
  • Karttunen, Lauri; Koskenniemi, Kimmo; Kaplan, Ronald (Center for the Study of Language and Information, Stanford University, 1987)
  • Gritsevich, Maria; Vinnikov, Vladimir; Kohout, Tomas; Toth, Juraj; Peltoniemi, Jouni; Turchak, Leonid; Virtanen, Jenni (University of Arizona, Dept. of Geosciences, 2014)
    Abstract–In this study, we conduct a detailed analysis of the Košice meteorite fall (February28, 2010), to derive a reliable law describing the mass distribution among the recovered fragments. In total, 218 fragments of the Košice meteorite, with a total mass of 11.285 kg, were analyzed. Bimodal Weibull, bimodal Grady, and bimodal lognormal distributions are found to be the most appropriate for describing the Košice fragmentation process. Based on the assumption of bimodal lognormal, bimodal Grady, bimodal sequential, and bimodal Weibull fragmentation distributions, we suggest that, prior to further extensive fragmentation in the lower atmosphere, the Košice meteoroid was initially represented by two independent pieces with cumulative residual masses of approximately 2 and 9 kg, respectively. The smaller piece produced about 2 kg of multiple lightweight meteorite fragments with the mean around 12 g. The larger one resulted in 9 kg of meteorite fragments, recovered on the ground, including the two heaviest pieces of 2.374 kg and 2.167 kg with the mean around 140 g. Based on our investigations, we conclude that two to three larger fragments of 500–1000 g each should exist, but were either not recovered or not reported by illegal meteorite hunters.
  • Holmgren, Noel Michael Andre; Norrstrom, Niclas; Aps, Robert; Kuikka, Sakari (PUBLIC LIBRARY OF SCIENCE, 2014)