Analysis of Korean astronomical records with Chinese equatorial coordinates     

K.W. Lee 《Astronomische Nachrichten》2012,333(7):648-659

The historical documents of ancient Korea contain abundant records on various astronomical phenomena. The historical documents of the Joseon dynasty contain observational values based on Chinese equatorial coordinate system (i.e., angular distances from the reference star of a lunar mansion and the North Pole). However, quantitative analysis of the observational values has not been carried out. In this study, we investigate the observational accuracy during the Joseon dynasty by comparing the astronomical records of Joseonwangjo Sillok (Annals of the Joseon Dynasty) and Seungjeongwon Ilgi (Daily Records of the Royal Secretariat) with modern astronomical calculations. Consequently, we find that the observational accuracy during the early Joseon dynasty was approximately 1°.2 and 0°.3 in the right ascension and declination, respectively. On the other hand, we find that the observational accuracy during the later Joseon dynasty was considerably poor. Observations of Halley's comet in 1759 were off by approximately 7° in declination. We believe that further investigation is required to verify the reason for this poor accuracy. Thus, we list the complete records used for this study in the appendix. We believe that these records also can contribute to modern studies on phenomena such as supernovae or Halley's comet. In conclusion, we believe that this study is useful for understanding ancient Korean astronomical records, even though we have considered a small number of astronomical events (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Breaking Out: The Opportunities and Challenges of Multi-Method Research inPopulation Geography     

《The Professional geographer》2013,65(1):76-89

Research traditions exert a powerful influence over the thinking of academic researchers. In population geography an entrenched empiricism and a reluctance to engage in wider debates on theory and method within human geography have resulted in a degree of separate development. Such methodological complacency has, until recently, threatened to undermine population geography's role within the discipline as a whole. Thus the discussion of multi-method research designs is of particular significance because it offers population geographers an opportunity to break out from the confines of a dominant research tradition and participate with other human geographers in an important methodological debate. This paper seeks not only to provide a critical overview of the current debate within population geography (as represented in the preceding papers in this Focus section) but also to extend that debate by raising issues of much more general concern. I argue that there are dangers in drawing the terms of the debate too narrowly. If we are to understand the nature and potential of multi-method research, we must first pose fundamental questions about the interrelationships among methods, data, and research problems. Pragmatic views on the choice of research method are inadequate because they fail to recognise the theory-driven nature of research. Only once we have achieved a better understanding of the philosophical grounding of research strategies will the opportunities afforded by multi-method research be fully realised.  相似文献   

Causal models as multiple working hypotheses about environmental processes   总被引：6，自引：0，他引：6  

Keith Beven 《Comptes Rendus Geoscience》2012,344(2):77-88

The environmental modeller faces a dilemma. Science often demands that more and more process representations are incorporated into models (particularly to avoid the possibility of making missing process errors in predicting future response). Testing the causal representations in environmental models (as multiple working hypotheses about the functioning of environmental systems) then depends on specifying boundary conditions and model parameters adequately. This will always be difficult in applications to a real system because of the heterogeneities, non-stationarities, complexities and epistemic uncertainties inherent in environmental prediction. Thus, it can be difficult to define the information content of a data set used in model evaluation and any consequent measures of belief or verisimilitude. A limit of acceptability approach to model evaluation is suggested as a way of testing models, implying that thought is required to define critical experiments that will allow models as hypotheses to be adequately differentiated.  相似文献   

地理学的模型建设及其选择标准——简析非欧几何学对地理学研究方法的影响     

陈彦光 《福建地理》2008,(4):1-7

非欧几何学产生以后,科学研究的主要任务由寻求真理转变为建设模型,地理科学的任务也理当发生相应的转向．像其他科学分支一样,地理学的研究目标不再是发现真理,而是提出假设、建立模型．判断一个地理理论模型好坏的标准不是模型的假设是否符合实际,而是该模型对现实世界的解释和预言能力．在模型的解释和预言能力一定的情况下,模型越是简单,就越是可取;在模型的复杂程度一定的情况下,模型的解释和预言能力越强,就越是优越．当一个地理模型不仅仅对地理现象具有刻画能力,而且对其他相关领域具有某种启示作用的时候．该模犁就具有超学科的理论意义或者研究价值．  相似文献   

复合含油气系统的提出及其在叠合盆地油气资源预测中的作用   总被引：10，自引：1，他引：9  

赵文智张光亚  汪泽成 《地学前缘》2005,12(4):458-467

针对中国叠合盆地油气流动特征以及成藏规律,提出了复合含油气系统的概念。基于叠合盆地演化特征和油气地质特点分析,将复合含油气系统分为继承型、延变型与改造型三种基本类型。由于各含油气系统共享要素的不同,构成了“共盖复合”、“贯通复合”、“叠置复合”与“交叉复合”等多种复合方式;复合含油气系统的边界即是多个油气系统复合后的最大外边界。对复合含油气系统研究与评价,倡导以过程重建为主导的“顺藤摸瓜”的研究思路,并相应提出了“六定”的评价流程,对叠合盆地油气资源潜力评价与分布预测具有重要作用。  相似文献   

关于抗震设计规范与地震动区划图的有关探讨   总被引：1，自引：1，他引：0  

王克海  李刚  韦韩  姜震宇  李茜 《震灾防御技术》2008,3(4):413-420

本文总结了国内外桥梁抗震设计规范和建筑结构抗震设计规范的设计思想和设计方法,介绍了我国和美国地震动参数区划图的发展和现状,对比分析了抗震规范使用地震区划图的情况。针对我国抗震设计规范和地震动参数区划图的现状,提出了两条建议：（1）地震动参数区划图编制部门应直接提供多水准的地震动参数区划图;（2）抗震设计规范应彻底抛弃设防烈度概念,以地震重现期取代原地震危险程度标示方法。  相似文献   

The 1998 outburst and history of the June Boötid meteor shower     

R. Arlt  J. Rendtel  P. Brown  V. Velkov  W. K. Hocking  J. Jones 《Monthly notices of the Royal Astronomical Society》1999,308(3):887-896

The June Boötid meteor shower (sometimes referred to as the Draconids) surprised a number of regular and casual observers by an outburst with maximum zenithal hourly rates (ZHRs) near 100 on 1998 June 27 after a quiescent period of several decades. A total of 1217 June Boötid meteors were recorded during regular visual meteor observations throughout this outburst. An average population index of r =2.2±0.10 was derived from 1054 shower magnitude estimates. The broad activity profile with ZHR>40 lasting more than 12 h and the large spread of apparent radiants in 1998 resemble the 1916 and 1927 outbursts. The peak time is found to be at about λ _⊙=95°.7 (2000.0); peak ZHRs are of the order of 200, whereas reliable averages reach only 81±7. The period of high ZHRs covered by a single observer implies a full width at half-maximum of 3–4 h. The resulting maximum flux of particles causing meteors brighter than +6.5 mag is between 0.04 and 0.06 km⁻² h⁻¹. The average radiant from photographic, radar and visual records is α =224°.12, δ =+47°.77. The observed activity outbursts in 1916, 1927 and 1998 are not related to the orbital period or the perihelion passages of the parent comet 7P/Pons–Winnecke. These are probably a consequence of the effects of the 2:1 resonance with Jupiter.  相似文献   

基于现象教学法的“GIS常用软件应用”课程改革     

王莉  景海涛  杜久升 《测绘工程》2017,26(6)

"GIS常用软件应用"课程为GIS专业的一门专业课程。以"现象教学法"理念为指导,探讨GIS专业"GIS常用软件应用"课程的教学改革,包括教学内容、教学方式、考核方式的改革。实践表明:采用现象教学法既尊重学生的主体地位、培养学生学习兴趣,又提高学生的创新精神和团队合作意识,通过采用灵活的教学手段和教学内容可以显著提高教学效果。  相似文献   

地理学本体论：内涵、性质与理论价值   总被引：2，自引：0，他引：2  

刘凯  汤茂林  刘荣增  秦耀辰 《地理学报》2017,72(4):577-588

科学哲学研究表明,本体论问题的探讨对于具体学科的科学哲学研究和理论研究都具有重要意义。本文界定了地理学本体论的内涵,讨论了地理学方法论、本体论和地理学哲学的关系,比较和分析了哲学本体论与地理学本体论之间的联系和区别,阐述了地理学本体论的性质,概括了地理学本体论的理论价值。地理学本体论包括两个层面：地理学家和地理学流派的哲学本体论观念、地理学理论的本体论承诺,地理学家的本体论影响和决定着地理学家的认识论、方法论和价值论选择,而某个地理学理论的本体论承诺则是该理论得以成立的前提和基础。  相似文献   

Variations of 14C around AD 775 and AD 1795 – due to solar activity     

R. Neuhuser  D. L. Neuhuser 《Astronomische Nachrichten》2015,336(10):930-954

The motivation for our study is the disputed cause for the strong variation of ¹⁴C around AD 775. Our method is to compare the ¹⁴C variation around AD 775 with other periods of strong variability. Our results are: (a) We see three periods, where 14C varied over 200 yr in a special way showing a certain pattern of strong secular variation: after a Grand Minimum with strongly increasing ¹⁴C, there is a series of strong short‐term drop(s), rise(s), and again drop(s) within 60 yr, ending up to 200 yr after the start of the Grand Minimum. These three periods include the strong rises around BC 671, AD 775, and AD 1795. (b) We show with several solar activity proxies (radioisotopes, sunspots, and aurorae) for the AD 770s and 1790s that such intense rapid ¹⁴C increases can be explained by strong rapid decreases in solar activity and, hence, wind, so that the decrease in solar modulation potential leads to an increase in radioisotope production. (c) The strong rises around AD 775 and 1795 are due to three effects, (i) very strong activity in the previous cycles (i.e. very low ¹⁴C level), (ii) the declining phase of a very strong Schwabe cycle, and (iii) a phase of very weak activity after the strong ¹⁴C rise – very short and/or weak cycle(s) like the suddenly starting Dalton minimum. (d) Furthermore, we can show that the strong change at AD 1795 happened after a pair of two packages of four Schwabe cycles with certain hemispheric leadership (each package consists of two Gnevyshev‐Ohl pairs, respectively two Hale‐Babcock pairs). We show with several additional arguments that the rise around AD 775 was not that special. We conclude that such large, short‐term rises in ¹⁴C (around BC 671, AD 775, and 1795) do not need to be explained by highly unlikely solar super‐flares nor other rare events, but by extra‐solar cosmic rays modulated due to solar activity variations. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献