Using the Information Structure Model to Compare Profile-Based Information Filtering Systems     

Yuval Elovici  Bracha Shapira  Paul B. Kantor 《Information Retrieval》2003,6(1):75-97

In the IR field it is clear that the value of a system depends on the cost and benefit profiles of its users. It would seem obvious that different users would prefer different systems. In the TREC-9 filtering track, systems are evaluated by a utility measure specifying a given cost and benefit. However, in the study of decision systems it is known that, in some cases, one system may be unconditionally better than another. In this paper we employ a decision theoretic approach to find conditions under which an Information Filtering (IF) system is unconditionally superior to another for all users regardless of their cost and benefit profiles.It is well known that if two IF systems have equal precision the system with better recall will be preferred by all users. Similarly, with equal recall, better precision is universally preferred. We confirm these known results and discover an unexpected dominance relation in which a system with lower recall will be universally preferred provided its precision is sufficiently higher.  相似文献   

关于三段论一般规则存在依据的思考     

马养新 《陕西师范大学学报(哲学社会科学版)》2001,30(1):83-91

三段论理论是人类有史以来第一个真正的理论体系.选择有效式是构造三段论理论重要的一环.三段论一般规则是一种最简单实用的选择方法,但却存在理由不足的缺陷.包含关系的概念内涵之间所具有的蕴涵关系,能够单一地引申或者说充分地论证三段论全部一般规则,甚至能直接识别出三段论每一个具体的有效式,从而为采用一般规则做有效式选择标准的三段论理论提供了可靠的理论依据.  相似文献   

科技论文文体结构所体现的美学特征   总被引：2，自引：0，他引：2  

高时阔  黎文丽  郭开选  赵青娥 《编辑学报》2006,18(3):173-175

作为审美对象的科技论文,是作者通过科学实验和理性思维创造的一种美的结晶,其文体结构的美学特征主要体现为学术创新、真实可靠的科学美,结构严谨、层次清晰的形式美和准确简洁、朴实明白的语言美.  相似文献   

图书馆评估类型的理论重组   总被引：5，自引：0，他引：5  

熊伟 《图书情报工作》2006,50(11):127-130

针对学界和业界对图书馆评估类型问题迫切需要进行理论上的重组这一状况，论述图书馆评估在理论上存在着一个开放的类型体系。从图书馆评估的本质属性出发，可以把它划分为鉴定性、建设性、发展性和审美性等实质评估类型;从图书馆评估的外部属性出发，可以把它分别划为广义和狭义、前置性和形成性及总结性、外部和内部、相对和绝对等形式评估类型。  相似文献   

传统概念问题的当代形式逻辑剖析     

龚启荣 《黔南民族师范学院学报》2005,25(5):20-25

尽管传统形式逻辑在概念问题上不研究大于1的n元名词而只研究仅占n分之1的1元名词，可是在这n分之1的研究中仍然存在着不少缺陷。譬如，关于概念的定义至今仍不能自圆其说；有些概念种类划分不合理；给概念内涵下的定义产生歧义；给普遍概念下的定义过宽；等等。传统形式逻辑是真正的逻辑科学，我们剖析的目的是深深地切望传统形式逻辑深刻正确的主导思想和久胜不衰的理论成果得到发扬光大。  相似文献   

Timescales for exploratory tactical behaviour in football small-sided games     

Angel Ric  Robert Hristovski  Bruno Gonçalves  Lorena Torres  Jaime Sampaio  Carlota Torrents 《Journal of sports sciences》2016,34(18):1723-1730

The aim of this study was to identify the dynamics of tactical behaviour emerging on different timescales in football small-sided games and to quantify short- and long-term exploratory behaviour according to the number of opponents. Two teams of four professional male footballers played small-sided games against two different teams with a variable number of opponents (3, 5 and 7). Data were collected using a combination of systematic observation and a non-differential global positioning system (15 Hz). The temporal diversity and structural flexibility of the players were determined by calculating the dynamic overlap order parameter q, entropy and trapping strength. Analysis of the exploratory dynamics revealed two different timescales, forming a different metastable landscape of action for each constraint. Fast dynamics lasted on average a few seconds and consisted of changes in tactical patterns. The long timescale corresponded to the shared tasks of offence and defence lasting tens of seconds. The players’ tactical diversity decreased with an increasing number of opponents, especially in defence. Manipulating numerical imbalance is likely to promote changes in the diversity, unpredictability and flexibility of tactical solutions. The fact that the temporally nested structure of constraints shaped the emergence of tactical behaviour provides a new rationale for practice task design. The manipulation of numerical imbalance on the timescale of a few tens of seconds, on which the exploratory behaviour of players saturates, may help coaches to optimise the exploratory efficiency of the small-sided games.  相似文献   

民营企业融资约束的异质性与收敛性分析:来自沪深A股的经验数据     

戴瑞姣 《教育教学论坛》2019,(26):64-65

以2007-2017年我国沪深A股的上市民营企业为研究对象,通过计算SA指数,考察我国民营企业融资约束的异质性和收敛性。研究发现,民营企业普遍面临着较为严重的融资约束,区域异质性体现不明显,行业异质性存在,民营企业的融资约束呈现σ-和β-收敛。  相似文献   

C语言中的自增/自减运算符     

孙义欣  许卫华  孟令波 《潍坊教育学院学报》2006,19(4):17-18

本文根据笔者多年的C语言编程经验,详细归纳了++/--运算符在解题过程中应注意的多个方面的事项,是对教材的一个非常有益的补充,可用于C语言教学的参考,也有助于初学者的自学。  相似文献   

再论RP技术在设计美学中的运用     

徐炜  袁涛 《昆明大学学报》2007,18(4):17-19

RP技术能够快速成型得到实态模型,设计美学则使产品呈现美观的状态。RP技术在设计美学中的运用,就是利用RP技术的快速性和直观性,在设计制作过程中,以设计美学的原则和方法来规避不恰当的因素。使产品在设计与制造过程中,体现出形式美与技术美,获得高品质的产品,对加快设计与制造业发展,提高产品的市场竞争力具有重要的现实意义。  相似文献   

大学适度规檩的取值条件分析     

刘志民 《黑龙江高教研究》2004,(11):6-9

规模经济理论被应用于大学适度规模研究，是基于大学资源优化配置后能产生规模效益的认识，已经采用的研究方法主要有：统计成本分析法、适生存检验法和MR与MC分析法。规模经济理论及研究方法的局限性及高等教育的特殊性，使得大学最小有效规模或最佳规模的研究结果有很大差异。因此，大学在选择适度规模时应综合考虑基本办学条件、学校发展定位、教育市场需求等约束条件，根据自身资源利用与再生潜力确立一个相对合理的规模区间。  相似文献