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Episodes 2008年第1期31卷 73-81页

作者： Barbara Wohlfarth Svante Bjoerck Svend Funder Michael Houmark-Nielsen Olafurlngolfsson juha-pekka lunkka Jan Mangerud Matti Saarnisto Tore Vorren Department of Geology and Geochemistry Stockholm University SE-106 91 Stockholm Sweden. GeoBiosphere Science Centre Quaternary Sciences Soelvegatan 12 SE-223 62 Lund Sweden. Geological Museum University of Copenhagen Фster Voldgade 5-7 DK-1350 Copenhagen K Denmark. Institute of Geography and Geology University of Copenhagen Фstervoldgade 10 Dk-1350 KФbenhavn K Denmark. Department of Geology University of Iceland Askja ls-101 Reykjavfk Iceland. Institute of Geosciences P.O. Box 3000 FI-90014 University of Oulu Finland. Department of Earth Science and the Bjerknes Centre for Climate Research University of Bergen Allegatan 41 N-5007 Bergen Norway. Finnish Academy of Science and Letters Mariankatu 5 FI-00170 Helsinki Finland. Department of Geology University of TromsФ Dramsveien 201 N-9037 TromsФ Norway.

The Nordic countries have experienced multiple glaciations and intervening interglacials during the last ca. 2.5-3 million years. Although evidence from Greenland and Iceland shows that ice sheets started to expand some time before 3 Ma, little is known about the glaciations and intervening interglacials older than the last Glacial Maximum due to repeated phases of glacial erosion and reworking. The extensive Saalian glaciation （c. 140 ka BP） contributed to high sea levels in Greenland and in the Baltic area during the early part of the last interglacial （Eemian）. Temperatures were about 5 ℃ higher during the Eemian than they are today and the Greenland ice sheet was reduced to about half of its present size, causing globally higher sea levels than we have today. Ice extent in Fennoscandia was restricted during early Weichselian stadials, but middle Weichselian ice advances in Scandinavia reached as far as Denmark. During the Last Glacial Maximum, large ice sheets were present in all Nordic countries and coalesced with neighboring ice sheets. Deglaciation commenced around 17-15 ka BP in most areas and was promoted by rapidly rising global sea level and glacial isostasy. The Younger Dryas cold event（c. 12.6-11.5 ka BP） is seen as a short-term re-advance, still-stand or fluctuation of land-based ice sheet margins. Around 7-9 ka BP ice sheets had disappeared or had attained their present size. While uplift is still going on in some regions, others are subject to submergence. The different stages of development of the Baltic Sea are an example of how the intricare interplay between glacial eustasy and isostasy influences sedimentation, basin size and drainage patterns.

关键词：冰川时代北欧地区第四纪间冰期

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Electricity demand forecasting at distribution and household levels using explainable causal graph neural network

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Energy and AI 2024年第2期16卷 385-395页

作者： Amir Miraki pekka Parviainen Reza Arghandeh Department of Computer Science Electrical Engineering and Mathematical SciencesWestern Norway University of Applied SciencesBergenNorway Department of Informatics University of BergenBergenNorway

Forecasting electricity demand is an essential part of the smart grid to ensure a stable and reliable power grid. With the increasing integration of renewable energy resources into the grid, forecasting the demand for electricity is critical at all levels, from the distribution to the household. Most existing forecasting methods, however, can be considered black-box models as a result of deep digitalization enablers, such as deep neural networks, which remain difficult to interpret by humans. Moreover, capture of the inter-dependencies among variables presents a significant challenge for multivariate time series forecasting. In this paper we propose eXplainable Causal Graph Neural Network (X-CGNN) for multivariate electricity demand forecasting that overcomes these limitations. As part of this method, we have intrinsic and global explanations based on causal inferences as well as local explanations based on post-hoc analyses. We have performed extensive validation on two real-world electricity demand datasets from both the household and distribution levels to demonstrate that our proposed method achieves state-of-the-art performance.

关键词： Causal inference Electricity demand forecasting Explainable artificial intelligence(XAI) Graph neural network

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Two decades of fire activity over the PEEX domain:a look from space,with contribution from models and ground-based measurements

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Big Earth Data 2024年第2期8卷 350-396页

作者： Larisa Sogacheva Timo H.Virtanen Anu-Maija Sundström pekka Kolmonen Mikhail Sofiev Hanna K.Lappalainen Antti Arola Finnish Meteorological Institute Climate Research ProgrammeHelsinkiFinland Finnish Meteorological Institute Space and Earth Observation CentreHelsinkiFinland Institute for Atmospheric and Earth System Research/Physics Faculty of ScienceUniversity of HelsinkiHelsinkiFinland

It has been suggested that forest fires will become more frequent/intense with changing climate,which would increase aerosol/gas emissions into the atmosphere.A better under-standing of the relations between meteorological conditions,fires,and fire emissions will help estimate the climate response via forest *** this study,we use ERA5 meteor-ological products,including temperature,precipitation,and soil moisture,to explain the frequency of forest fires and the amount of radiant energy released per time unit by burning vegetation(fire radiative power,FRP).We explore the relation-ships between satellite-retrieved fire products and aerosol properties(aerosol optical depth,AOD),carbon monoxide(CO),formaldehyde(HCHO),and nitrogen dioxide(NO_(2))con-centrations over the PEEX domain,which covers different vegetation zones(***/grasslands,forest,arctic tun-dra)of Pan-Eurasia and *** analyse the concentrations of black carbon and absorbing organic carbon using groundbased AErosol RObotic *** analysis covers the months of May to August from 2002 to *** show posi-tive temperature trends in the Northern zone(>65°N)in June and August(1.56°C and 0.64°C,respectively);all statistically significant trends for precipitation and soil moisture are *** can explain increased fire activity in Siberia over the recent years(2019-2022).Over the whole PEEX domain,FC and FRP trends remain insignificant or negative;a decrease in AOD may address those negative *** show that intrasummer variations exist for cropland/grassland fires,which occur most often in May and August,while Siberian forest fires occur more often in July and *** show that CO concentration has been gradually decreasing in the last two decades in May and *** trends are negative in May,June,and over summer for all regions,in July in Europe,China,the Southern zone(<55°N),and the PEEX *** trends are not significant in all ***_(2)trends are positive in May and

关键词： PEEX wild fires satellite trend enhancement ratios

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校园城市村落芬兰埃斯波

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世界建筑导报 2024年第2期39卷 104-105页

作者： Juho Grönholm Antti Nousjoki Janne Teräsvirta Samuli Woolston Willem Barendregt Vladimir Ilic Julius Kekoni Auvo Lindroos Aleksi Niemeläinen pekka Sivula pekka Tainio Jussi Vuori Haley Zhou ErikaÖsterlund ALA建筑师事务所

ALA建筑师事务所在阿尔托大学的2015校园国际设计竞赛中提出了“大型联合建筑群——活动孵化器”的理念。他们的目标是连接现有的结构和项目,创建一个新的区域热点,一个充满街道生活气息的城市集中区,促进创造力的展示。

关键词：建筑师事务所国际设计竞赛孵化器创造力生活气息阿尔托大学校园集中区

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Sprayformed Hot Work Steels for Rapid Tooling

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Journal of Materials Science & Technology 2003年第Z1期19卷 169-172页

作者： Yunfeng Yang Simo-pekka Hannula VTT Industrial Systems P.O.BOX 1703 FIN-02044 VTT Finland VTT Industrial Systems P.O.BOX 1703 FIN-02044 VTT Finland

The present work compares microstructures of hot work steels made by different processes, that is, by sprayforming,by casting, and a commercially supplied H13 steel. Material benefits are recognized by sprayforming hot working tools such as die inserts for hot forging. The sprayformed hot work steels present a fine and homogeneous microstructure,which implies that, at a similar toughness level, the sprayformed steel can be higher alloyed, so that the thermal fatigue and wear resistance at elevated temperatures can be improved. A series of steels with higher vanadium content than commercial hot work steels are developed. There are no segregation and carbide network problems usually encountered in conventional ingot/forging processed high-vanadium steels. Microstructure and hardness of the new sprayformed steels are studied under different heat treatment conditions. It is justified that these sprayformed steels can be directly used for tooling without high temperature hardening. Sprayforming the tool steels onto a precision ceramic mould is demonstrated to extend the technoeconomical benefits, so that a net shape production tool can be rapidly *** of the rapid tooling process are also discussed.

关键词： Rapid tooling, Sprayforming, Hot working steel, Die insert

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Mappings of Finite Distortion: Formation of Cusps Ⅲ

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Acta Mathematica Sinica,English Series 2010年第5期26卷 817-824页

作者： pekka KOSKELA juhani TAKKINEN Department of Mathematics and Statistics University of Jyvskyl

We give sharp integrability conditions on the distortion of a planar homeomorphism that maps a standard cusp onto the unit disk.

关键词： cusp finite distortion planar homeomorphism

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Lebesgue points via the Poincar inequality

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Science China Mathematics 2015年第8期58卷 1697-1706页

作者： KARAK Nijjwal KOSKELA pekka Department of Mathematics and Statistics University of Jyvskyl

We show that in a Q-doubling space （X, d, μ）, Q 〉 1, which satisfies a chain condition, if we have a Q-Poincare inequality for a pair of functions （u, g） where g ∈ LQ（X）, then u has Lebesgue points 7-th-a.e. for h（t） = log1-Q-c（1/t）. We also discuss how the existence of Lebesgue points follows for u ∈ W1,Q（x） where （X, d, μ） is a complete Q-doubling space supporting a Q-Poincar; inequality for Q 〉 1.

关键词： Lebesgue point Poincar6 inequality Q-doubling space

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Sub-Terahertz Channel Sounder: Review and Future Challenges

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China Communications 2023年第6期20卷 26-48页

作者： Yejian Lyu pekka Kyosti Wei Fan Deparment of Electronic Systems Aalborg UniversityAalborg Ost 9220Denmark Center for Wireless Communication-Radio Technology(CWC-RT) Oulu UniversityOulu 90570Finland Keysight Technologies Finland Oy Oulu 90630Finland

Due to the large amount of unused and unexplored spectrum resources, the so-called subTerahertz(sub-THz) frequency bands from 100 to 300 GHz are seen as promising bands for the next generation of wireless communication systems. Channel modeling at sub-THz bands is essential for the design and deployment of future wireless communication systems. Channel measurement is a widely adopted method to obtain channel characteristics and establish mathematical channel models. Channel measurements depend on the design and construction of channel sounders. Thus, reliable channel sounding techniques and accurate channel measurements are required. In this paper, the requirements of an ideal channel sounder are discussed and the main channel sounding techniques are described for the subTHz frequency bands. The state-of-the-art sub-THz channel sounders reported in the literature and respective channel measurements are presented. Moreover, a vector network analyzer(VNA) based channel sounder, which supports frequency bands from 220 to330 GHz is presented and its performance capability and limitation are evaluated. This paper also discussed the challenge and future outlook of the sub-THz channel sounders and measurements.

关键词： radio propagation beyond 5G communication sub-terahertz channel sounding techniques

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Does boldness explain vulnerability to angling in Eurasian perch Perca fluviatilis？

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Current Zoology 2016年第2期62卷 109-115页

作者： Anssi VAINIKKA Ilkka TAMMELA pekka HYVARINEN Department of Biology University of Eastern Finland PO Box 111 FI 80101 Joensuu Finland Natural Resource Institute Finland Manamansalontie 90 88300 Paltamo Finland

Consistent individual differences （CIDs） in behavior are of interest to both basic and applied research, because any selection acting on them could induce evolution of animal behavior. It has been suggested that CIDs in the behavior of fish might explain individual differences in vulnerability to fishing. If so, fishing could impose selection on fish behavior. In this study, we assessed boldness-indicating behaviors of Eurasian perch Perca fluviatilis using individually conducted experiments measuring the time taken to explore a novel arena containing predator （burbot, Lota Iota） cues. We studied if individual differences in boldness would explain vulnerability of individually tagged perch to experimental angling in outdoor ponds, or if fishing would impose selection on boldness-indicating behavior. Perch expressed repeatable individual differences in boldness-indicating behavior but the individual boldness-score （the first principal component） obtained using principal component analysis combining all the measured behavioral responses did not explain vulnerability to experimental angling. Instead, large body size appeared as the only statistically significant predictor of capture probability. Our results suggest that angling is selective for large size, but not always selective for high boldness.

关键词： behavior fishing-induced evolution fishing vulnerability growth personality selection

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Traces of weighted function spaces: Dyadic norms and Whitney extensions

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Science China Mathematics 2017年第11期60卷 1981-2010页

作者： KOSKELA pekka SOTO Tomas WANG Zhuang Department of Mathematics and Statistics University of Jyvskyl

The trace spaces of Sobolev spaces and related fractional smoothness spaces have been an active area of research since the work of Nikolskii, Aronszajn, Slobodetskii, Babich and Gagliardo among others in the 1950's. In this paper, we review the literature concerning such results for a variety of weighted smoothness spaces. For this purpose, we present a characterization of the trace spaces(of fractional order of smoothness),based on integral averages on dyadic cubes, which is well-adapted to extending functions using the Whitney extension operator.

关键词： trace theorems weighted Sobolev spaces Besov spaces Triebel-Lizorkin spaces

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