首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
This paper proposes an a fortiori case study method of testing Bachrach and Baratz's 1962, 1963, 1970 well-known hypotheses about the second face of power. This face of power is allegedly characterised by exclusionary agendasetting; elites exclude the interests and demands of the poor from the policy agenda. A working assumption of the paper is that exclusionary agenda-setting may be quite infrequent. If we can specify the conditions under which it is relatively likely to occur, and then investigate cases which meet most or all of these conditions, we may be able to discover the minimum set or sets of conditions which have to be met. We could then make a fortiori inferences about other less stringent sets of conditions under which it would rarely if ever occur.  相似文献   

2.
This article is the first of two companion articles addressing the statistical characterization of seismic demand. Performance-based earthquake engineering methodologies often require the characterization of central value estimates of structural demand. Since outliers can occur in the data, central value estimates should be determined by robust estimation methods. The performance of 50 robust central value estimators is evaluated, for different sample sizes, using the chord rotation, curvature, shear force, and inter-story drift demands obtained after analyzing five reinforced concrete structures under real earthquake records scaled to several intensities. Based on the results, seven estimators are proposed for different sample sizes.  相似文献   

3.
The column members of steel moment frames undergo high axial forces as well as inelastic rotations during a severe seismic event. The boundaries of these simultaneous structural demands on the columns of special moment frames have been investigated in this research. Based on the results of this investigation, dual cyclic loading protocols have been developed that represent both axial force and lateral deformation demands. Contrary to other loading scenarios that have been implemented in previous studies on steel columns, the loading protocols developed in this study include simultaneous axial and lateral loading cycles with varying amplitudes. The level of axial forces and story drifts tolerated by the columns of some typical Special Moment Frames (SMFs) has been investigated through performing nonlinear dynamic analyses. These frames have been selected with several configurations and different number of stories. The results of the nonlinear dynamic analyses have been processed to assess cumulative and instantaneous seismic demands on the columns of the chosen typical frames. Subsequently, dual cyclic loading protocols have been developed such that exerting these loading protocols on individual steel columns can result in structural effects close to the general seismic demands assessed in this study. Two separate dual loading protocols have been introduced for Design Earthquake (DE) and Maximum Considered Earthquake (MCE) seismic intensity levels.  相似文献   

4.
Many Western universities are responding to the demands of globalisation by attempting to internationalise their curricula—that is, to introduce an element of multiculturalism. This project derives its rationale from three assumptions: (1) the globalisation process is a viable agenda for a sustainable and just future for all people; (2) it is the responsibility of the university to respond faithfully to current demands of Western society—that is, in this case, to the demands of globalisation; and, (3) given the first two assumptions, internationalisation of the curriculum is a logical response. It is argued that the first two assumptions need to be explicitly recognised and then rigorously questioned. This must be done by academics themselves, and as a joint project with students in the classroom. This questioning amounts to challenging the foundational concepts of contemporary Western civilisation. New directions for the future may thus emerge from the classroom. The core concepts of other cultures may be seen as an asset in this process, giving an entirely new meaning to the term ‘internationalisation of the curriculum’.  相似文献   

5.
Probabilistic models have been developed in a previous study by the authors to estimate the seismic deformation demands on structural components of reinforced concrete (RC) bridges with two-column bents. However, such models should be updated to reflect the latest laboratory of field data. Using a Bayesian approach, this article updates a currently available probabilistic model for the deformation demands of columns in bridges with two-column RC bents. The updated model incorporates information from newly available experimental data from shake table tests conducted based on a record of the 1994 Northridge Earthquake for a structural system with three bents with two columns per bent. The updated model is more accurate than the previous one in predicting the deformation demand of bridges with two-column RC bents and reduces the statistical uncertainty due to the addition of new data. As an application, fragility estimates for an example bridge are computed using the updated model both at the component (column) and system (bridge) levels.  相似文献   

6.
A simplified model useful for assessing economic losses due to moderate seismicity events in urban areas has been developed by studying the behavior of buildings before yielding their structural system, allowing for nonuniform stiffness along their height. In particular, buildings are modeled as cantilever shear beams with uniform mass and parabolic reduction of lateral stiffness. This particular stiffness distribution is relevant, as it could be expected to occur in buildings where earthquake action is a critical structural design criterion. The equation of motion governing the dynamic behavior of the proposed model is solved analytically, finding mode shapes in terms of first and second zero-order Legendre functions. The solution is verified by comparing it with results obtained from fine mesh finite element models. The effect of reducing the lateral stiffness is then studied in the first five modes of vibration. Results include modal periods, mode shapes, modal participation factors, and derivatives of mode shapes. In general, it is found that effects of reduction of lateral stiffness in mode shapes are moderate when the lateral stiffness in the free end is smaller than about seventy percent of the lateral stiffness at the fixed end, but become significant for larger reductions. Effects are particularly important for the derivative of the mode shapes, which could play a significant role in estimating interstory drift demands in buildings. Model usefulness is showcased by analyzing a test case where both acceleration and drift demands are assessed by considering uniform beams and beams with parabolic stiffness variation, finding notable improvements by considering the latter.  相似文献   

7.
In this paper, a fairly effective procedure called dynamic load pattern (DLP), is proposed to account for the effects of near-fault ground motions in estimating the seismic demands of structures from pushover analyses. The seismic demands are obtained by enveloping the results of single-run conventional first-mode and single-run DLP pushover analyses. Improving the estimation of target displacement is another objective, implemented by performing response-spectrum analysis. Three special steel moment-resisting frames are considered and the seismic demands resulting from DLP are compared to those from the nonlinear time-history analysis as a benchmark solution, as well as to those predicted from modal pushover analysis.  相似文献   

8.
This paper reexamines the welfare implications of three pricing regimes (mill, uniform, and discriminatory) for a monopoly. Assuming linear demand and constant marginal costs, I show that with the introduction of endogenous location choice, uniform delivered pricing may provide the highest social welfare when demands in different markets are sufficiently heterogeneous; whereas discriminatory pricing always dominates uniform pricing when demands in different markets are similar.  相似文献   

9.
Under what conditions is gender equality policy advocacy successful? This article examines a segment of the largely quantitative comparative political science literature that seeks to answer this question. Recent scholarship emphasizes such factors as the strength of women's movements and the forms of opposition to which their policy demands give rise. However, one consequence of this approach is that the role of strategic choices made by feminist policy advocates is underestimated in explaining their successes. The article argues that understanding variation in the outcomes achieved by women's rights advocates requires close attention to the strategic capacity of policy entrepreneurs, assessed in terms of three inter‐related activities: (1) ‘framing’ policy demands; (2) forming and managing civic alliances; and (3) engaging with state entities without compromising organizational autonomy.  相似文献   

10.
基于问卷调查和GIS空间分析,深入剖析贫困户的致贫原因与帮扶需求,识别不同地区的主要致贫原因与帮扶需求类型,探明二者的空间分布特征及其内在关联,并提出相应减贫对策。结果显示:①贫困具有多维性和多重内涵,贫困户的致贫原因类型多样、程度不等,但总体上收入和社会保障不足是其最普遍的致贫原因。贫困地区的主要致贫原因差别显著,同一致贫原因的致贫程度呈现明显地域特征。②贫困户帮扶需求类型多样化,但加大资金帮扶力度、提高基本公共服务水平是其最迫切的需求。贫困地区最主要的帮扶类型差别明显,对同一帮扶类型的需求程度不尽相同。③致贫原因在较大程度上影响着帮扶需求的类型及其空间分布,但不起决定性作用,二者存在错位现象。  相似文献   

11.
This article investigates high-damping seismic demands and associated damping reduction factors in Eastern North America (ENA). A database of hybrid empirical records with moment magnitudes M ≥ 6.0 is first studied to evaluate 5%- to 30%-damped seismic demands. A new magnitude- and distance-based equation is proposed to predict ENA spectral displacements and then used to characterize their sensitivity to variations in period, magnitude, epicentral distance and site conditions. The proposed equation is also used to assess damping reduction factors in ENA. The results contribute to improved assessment of seismic demands in ENA while accounting for added-damping in structural seismic design.  相似文献   

12.
Bushfires (landscape fires) are a key Earth system process that affects humans and our societies and economies. In a recent article, we explored the coupling of humans to landscape fire through the lens of human health impacts of bushfire smoke. We noted that such an approach demands recognition of the indirect impacts and costs of bushfires that cannot be captured by simplistic proxies such as deaths directly attributable to a fire front. Evaluation of direct and indirect economic costs of bushfire disasters, and bushfire fire management remains a poorly developed research frontier that demands collaboration of expertise from a broad cross‐section of fields that often have limited experience of collaborating together. The need for such synthetic thinking about fire's place on Earth has spawned the discipline of pyrogeography.  相似文献   

13.
A prototype diesel generator equipped with a vibration isolation system consisting of restrained isolators (denoted as I/system) is quasi-statically and dynamically tested. Sequentially, the seismic simulation tests are conducted to further investigate the effectiveness of additional snubbers incorporated into the vibration isolation system (denoted as I/R system). Comparing the test results to the static design demands specified in ASCE 7-10, the recommended component amplification factor could represent the horizontal acceleration amplification phenomenon of the generator equipped with I/R system; however, the seismic force demands for static design of I/R system might not be appropriate and conservative enough.  相似文献   

14.
This article is the second of two companion articles that evaluate the seismic performance of steel moment-resisting frames with innovative beam-to-column connections that incorporate shape memory alloy (SMA) elements to enhance the energy dissipation characteristics of such frames. Building upon the finite element models of the three- and nine-story frames that were developed in the first article, the seismic demands on partially restrained frames with and without SMA elements are evaluated within a probabilistic framework. The results of this evaluation, expressed in the form of demand hazard curves, depict the effectiveness of the SMA connections in enhancing building performance over a range of demand levels. Martensitic SMA connections are most effective in controlling deformation demands on the frame from high levels of seismic intensity. In contrast, the recentering capability of superelastic SMA connections make them most suitable for reducing residual deformations in the structure, a reduction that is achieved at the expense of increased deformation demands during strong excitation. However, neither connection is uniformly beneficial at all hazard levels, suggesting that SMA systems must be tailored to the specific performance objectives for the building structural system.  相似文献   

15.
A procedure for deformation-controlled, or displacement-based, seismic design of multistorey RC buildings is proposed, implemented and applied for the full design of a four-storey RC structure. It is integrated into the overall structural design, along with the design for the non-seismic actions and consists of a ULS verification against the conventional strain limits for a frequent “serviceability” earthquake and of proportioning the compression reinforcement and the transverse reinforcement of critical regions of members to meet the member peak inelastic chord rotation demands under the “life-safety” seismic action. Quantitative rules and expressions are proposed for the estimation of (a) mean and upper-characteristic peak inelastic chord rotation demands, through appropriate linear-elastic analyses, and (b) mean and lower-characteristic values of member ultimate chord rotations, in terms of member geometric and material data.  相似文献   

16.
The juridical force of time forms a critical, but hitherto unexplored part of Hugo Grotius’s discourse on the justice of war and peace. Grotius defines war as a span of time in which disputed rights and armed conflicts between states are examined in reference to temporal coordinates. This method allows him to adjust otherwise static laws to meet the demands of times and spaces in an increasingly expanded world. In doing so, Grotius is also able to reconcile multiple layers of laws in a temporal framework, which suspends one layer of law, to be revived at later times. Finally, cautious in the use of the language of time, Grotius admits both that right demands immediacy, and that justice suffers delays. By this nexus of delay (mora) and emergency (necessitas), Grotius warns against the abuse of ‘time’ as a legal concept to justify unlawful claims, which still rings with alarm today.  相似文献   

17.
This article addresses the link between state feminism and democratization in the global South. The authors use the contrasting cases of Chile and Nigeria to show some of the factors that encourage women to exploit the opportunities presented by transitions to democracy, and link the outcome of state feminism to the strategies and discourses available to women during democratization. Based on evidence from the cases analysed, the authors propose that the strategic options available to women are shaped by at least three factors: (1) the existence of a unified women’s movement capable of making political demands; (2) existing patterns of gender relations, which influence women’s access to arenas of political influence and power; and (3) the content of existing gender ideologies, and whether women can creatively deploy them to further their own interests. State feminism emerged in Chile out of the demands of a broad–based women’s movement in a context of democratic transition that provided feminists with access to political institutions. In Nigeria, attempts at creating state feminism have consistently failed due to a political transition from military to civilian rule that has not provided feminists with access to political arenas of influence, and the absence of a powerful women’s movement.  相似文献   

18.
The United States has adopted a policy of geological disposal to resolve the problem of permanent disposition of highly radioactive spent nuclear fuel (SNF), but has been unable to implement this policy. This study draws upon literature on policymaking and interest group representation to examine that inability. It develops and explores a conceptualization of policy stalemate to analyze the case.
The study finds that the United States has arrived at a stalemate over SNF disposal policy in part because of its pluralist system of interest group representation, and in part because of the nature of the problem. The case demonstrates how, in a pluralist system, the interaction of interests over a complex and difficult policy problem can result in stalemate. Few of the involved interest groups have sufficient incentives to either implement current SNF disposal policy or to revisit the policy. Barring significant change in the nature of the problem, the balance of interests, or other factors in the policy environment, the stalemate will continue.
The central question of this symposium is how institutionalized systems of interest group representation manage competing demands for environmental protection with demands for energy. In the case of SNF disposal, the United States in effect is managing these competing demands by not addressing them. SNF disposal policy does not appear to pose directly the expected tradeoff between demands for environmental protection and accessible energy, as the conflict tends to be defined primarily in environmental terms. However, the trade-off is implicit; failure to resolve the problem will eventually impact continued access to nuclear energy.  相似文献   

19.
This article explores the potential and limits of contemporary economic rights‐based social activism by analysing an ongoing ‘Right to Food Campaign’ in India. While social movement theory often positions radical and reform strategies as alternatives, the RTF campaign has adopted a hybrid strategy: it has made a radical legal demand that the right to food be recognized as intrinsic to the right to life, while seeking implementation of this right through reform of existing government feeding programmes. The campaign's dual strategy reflects two distinct logics of human rights: a logic of non‐derogable rights that are immediately actionable (such as the right to life) and a logic of progressive implementation of rights that can only be realized fully over time (such as economic rights). This article draws on original data to demonstrate that the campaign's radical legal demands framed around the non‐derogable right to life have come closer to fulfilment than its reformist demands around progressive implementation. The RTF campaign's relative success in galvanizing legal action on hunger is tempered by ongoing challenges in sustaining grassroots‐level mobilization and influencing public policy implementation.  相似文献   

20.
Due to the large economical losses derived from recent seismic events, design methodologies that are based in the explicit control of the dynamic response of structures have been formulated. This article introduces, within the framework of performance-based design, a numerical methodology for the seismic design of structures that are expected to undergo severe cumulative plastic demands. The methodology explicitly considers and integrates: (1) the structural and non-structural performance of the building; (2) the life safety limit state; and (3) the prevention of low cycle fatigue.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号