Perfect Case Research Articles

On the finite‐time capture of a fast moving target

SummaryIn this work, we propose a feedback control law that enforces capture of a moving target by a slower pursuer in finite time. It is well known that if this problem is cast as a pursuit‐evasion differential game, then the moving target can always avoid capture by taking advantage of its speed superiority, provided that both the target and the pursuer are employing feedback strategies in the sense of Isaacs. Thus, in order to have a well‐posed pursuit problem, additional assumptions are required so that the pursuer can enforce capture of the faster target in finite time provided that it emanates from a set of ‘favorable’ initial positions, which constitute its winning set. In particular, we assume that the target's velocity either is constant and perfectly known to the pursuer (perfect information case) or can be decomposed into a dominant component, which is constant and known to the pursuer, and a second component that is uncertain and unknown to the pursuer (imperfect information case). It turns out that in both cases, the winning sets of the pursuer are pointed convex cones which have a common apex and a common axis of symmetry but different opening angles. We subsequently propose continuous feedback laws that enforce finite‐time capture while the pursuer never exits its winning set before capture takes place, for both cases. Copyright © 2016 John Wiley & Sons, Ltd.

Secure Beamforming Design for SWIPT in MISO Broadcast Channel With Confidential Messages and External Eavesdroppers

This paper studies the secure beamforming design for simultaneous wireless information and power transfer in a multiple-input single-output broadcast channel with confidential messages and external eavesdroppers, where each receiver adopts the power splitting (PS) scheme to decode information and harvest energy concurrently, and it is also seen as a potential eavesdropper for messages not intended for it. Our objective is to minimize the total transmit power while guaranteeing the individual secrecy rate and energy harvesting constraints at each receiver by jointly optimizing transmit beamforming vectors, artificial noise covariance, and receive PS ratios. Both scenarios of perfect and imperfect channel state information (CSI) at the transmitter are considered. For the perfect CSI case, we propose a two-stage optimization approach to solve the original non-convex problem global optimality, and also provide a low-complexity suboptimal solution based on the particle swarm optimization algorithm. Furthermore, we also extend the above result to the colluding eavesdroppers scenario. For the imperfect CSI case, we propose a worst-case-based robust formulation, where the CSI errors are norm-bounded. With the aid of S-Procedure, we derive the equivalent forms for constraints and then transform the non-convex robust design into a convex optimization problem. Simulation results are finally presented to demonstrate the performance of our proposed schemes.

Lucas Island Model: A 'Case Study' for Improving Students' Skill in Interpreting Macroeconomic Models

This paper develops a teaching apparatus of Lucas's 1972 model aimed at improving students' ability to interpret the underlying structure of modern macroeconomics models. In this respect, the Lucas island model represents the perfect study, since it falls into the narrow range of mile stone modern, macroeconomic models. Our teaching apparatus adds to the Lucas island model three distinctive features. First, it replaces the overlapping generation structure with the producer-shopper distinction within the household; second, it presents the classical perfect information case as the benchmark of the analysis and, finally, introduces a money market into the model.

Use of the Theoretical Domains Framework to evaluate factors driving successful implementation of the Accelerated Chest pain Risk Evaluation (ACRE) project.

BackgroundThe translation of healthcare research into practice is typically challenging and limited in effectiveness. The Theoretical Domains Framework (TDF) identifies 12 domains of behaviour determinants which can be used to understand the principles of behavioural change, a key factor influencing implementation. The Accelerated Chest pain Risk Evaluation (ACRE) project has successfully translated research into practice, by implementing an intervention to improve the assessment of low to intermediate risk patients presenting to emergency departments (EDs) with chest pain. The aims of this paper are to describe use of the TDF to determine which factors successfully influenced implementation and to describe use of the TDF as a tool to evaluate implementation efforts and which domains are most relevant to successful implementation.MethodsA 30-item questionnaire targeting clinicians was developed using the TDF as a guide. Questions encompassed ten of the domains of the TDF: Knowledge; Skills; Social/professional role and identity; Beliefs about capabilities; Optimism; Beliefs about consequences; Intentions; Memory, attention and decision processes; Environmental context and resources; and Social influences.ResultsSixty-three of 176 stakeholders (36 %) responded to the questionnaire. Responses for all scales showed that respondents were highly favourable to all aspects of the implementation. Scales with the highest mean responses were Intentions, Knowledge, and Optimism, suggesting that initial education and awareness strategies around the ACRE project were effective. Scales with the lowest mean responses were Environmental context and resources, and Social influences, perhaps highlighting that implementation planning could have benefitted from further consideration of the factors underlying these scales.ConclusionsThe ACRE project was successful, and therefore, a perfect case study for understanding factors which drive implementation success. The overwhelmingly positive response suggests that it was a successful programme and likely that each of these domains was important for the implementation. However, a lack of variance in the responses hampered us from concluding which factors were most influential in driving the success of the implementation. The TDF offers a useful framework to conceptualise and evaluate factors impacting on implementation success. However, its broad scope makes it necessary to tailor the framework to allow evaluation of specific projects.Electronic supplementary materialThe online version of this article (doi:10.1186/s13012-016-0500-9) contains supplementary material, which is available to authorized users.

Numerical study of the influence of interfacial roughness on the exchange bias properties of ferromagnetic/antiferromagnetic bilayers

Exchange bias and coercivity are both studied numerically in antiferromagnetic/ferromagnetic (AFM/FM) bilayers in the presence of a rough interface. The roughness is modeled by an AFM atomic mesa of variable width, in a periodic bidimensional system. Unlike the flat interface case, roughness can favor the presence of magnetic interfacial frustration or the formation of sharp magnetic domain walls pinned within the first AFM planes, inside the AFM mesa, in a Peierls potential well. We demonstrate by using athermal steepest-descent calculations that irreversible processes can occur during the hysteresis loops, when the AFM mesa width is less than half of the system period. In this case, the depinning of the domain wall from the Peierls potential well during the descending branch is not followed by its rewinding in a certain range of the AFM anisotropy. This leads to a large increase of both exchange bias and coercivity at low temperature and to an athermal training effect. When the thermal activation is taken into account by using Monte Carlo simulations, we show that a random walk of the domain wall occurs within the AFM layer. These processes induce changes in the AFM spin configuration when the system is cycled several times and produce a thermally activated training effect. Our simulations, interpreted in the context of periodic Peierls potential, provide an explanation for two important features of the exchange bias phenomenon, i.e., the thermal variation of its characteristic fields and the different contributions giving rise to the training effect (AFM bulk vs interface). More generally, the presence of interfacial atomic roughness reduces both exchange bias and coercivity with respect to the perfect interface case.

Oligopolio y estrategias de competencia en el mercado de minoristas en México

The overall objective of this paper is to make an approach to the analysis about competition and microeconomic dynamic on Mexican retail market. The research hypothesis is that Mexican retail market is not a perfect competition case, because it operates as an oligopoly market. So, it is assumed that this market is dominated by a few companies, where it is possible identify a leader and other companies that behave as followers. The competition in this market can take different shapes according to the corporations’ strategies. The price is not set by free market forces but by corporations and the competition for the domestic market, in which companies deploy a set complex competitive strategies where different combinations of variables are included, variables that are not just prices. Among these variables we can find, besides price, customer service; innovations; variety of offered products; market segmentation; product quality and sales infrastructure; mergers, acquisitions and partnerships; etc. Finally we can observe a concentrated oligopolistic behavior which highlights the existence of interdependence relationships among players.Some of these hypotheses were confirmed and nuanced, but the most important conclusion is that the behavior companies, markets and competition at the microeconomic level, are complex and evolves over time.

The Athabaskan Petition to the Inter-American Human Rights Commission: using human rights to respond to climate change

Climate change is predicted to have a particularly severe impact on the polar regions and their populations. In response to this, two northern indigenous groups independently petitioned the Inter-American Commission on Human Rights arguing that a State’s inaction on climate change resulted in violations of their human rights. This article compares the unsuccessful 2005 Inuit Petition to the pending 2013 Athabaskan Petition in order to try to predict if the pending petition can provide a means of obligating a State to respond to the threats posed by the changing climate. While it is difficult to know precisely why the Inuit Petition failed, this article concludes that the Athabaskan Petition may have a greater likelihood of success due to developments in the law and the Petition’s focus on black carbon emissions as the cause for climate change in the polar region. That said, the Athabaskan Petition does not provide a perfect case for assigning Canada responsibility for climate change and the recent actions of the Arctic Council may provide a better mechanism for reducing Arctic warming.

Communication and Randomness Lower Bounds for Secure Computation

In secure multiparty computation (MPC), mutually distrusting users collaborate to compute a function of their private data without revealing any additional information about their data to other users. While it is known that information theoretically secure MPC is possible among $n$ users (connected by secure and noiseless links and have access to private randomness) against the collusion of less than $n/2$ users in the honest-but-curious model, relatively less is known about the communication and randomness complexity of secure computation. In this work, we employ information theoretic techniques to obtain lower bounds on the amount of communication and randomness required for secure MPC. We restrict ourselves to a concrete interactive setting involving 3 users under which all functions are securely computable against corruption of a single user in the honest-but-curious model. We derive lower bounds for both the perfect security case (i.e., zero-error and no leakage of information) and asymptotic security (where the probability of error and information leakage vanish as block-length goes to $\infty$). Our techniques include the use of a data processing inequality for residual information (i.e., the gap between mutual information and G\'acs-K\"orner common information), a new information inequality for 3-user protocols, and the idea of distribution switching. Our lower bounds are shown to be tight for various functions of interest. In particular, we show concrete functions which have "communication-ideal" protocols, i.e., which achieve the minimum communication simultaneously on all links in the network, and also use minimum amount of randomness. Also, we obtain the first explicit example of a function that incurs a higher communication cost than the input length in the secure computation model of "Feige, Kilian, and Naor [STOC, 1994]", who had shown that such functions exist.

SimiVal, a multi-criteria map comparison tool for land-change model projections

The multiple uses of land-cover models have led to validation with choice metrics or an ad hoc choice of the validation metrics available. To address this, we have identified the major dimensions of land-cover maps that ought to be evaluated and devised a Similarity Validation (SimiVal) tool. SimiVal uses a linear regression to test a modelled projection against benchmark cases of, perfect, observed and systematic-bias, calculated by rescaling the metrics from a random case relative to the observed, perfect case. The most informative regression coefficients, p-value and slope, are plot on a ternary graph of ‘similarity space’ whose extremes are the three benchmark cases. SimiVal is tested on projections of two deliberately contrasting land-cover models to show the similarity between intra- and inter-model parameterisations. We find metrics of landscape structure are important in distinguishing between different projections of the same model. Predictive and exploratory models can benefit from the tool.

‘Maravalgate’ and its effects: a year of debate over the funding of French cinema

The French system of film funding allows French cinema to resist the hegemony of Hollywood better than any other European cinema. It is a reflection of France’s protective stance regarding its cultural products, a position that has long been expressed in its strong defence of the principle of ‘cultural exception’ in free trade agreements between the European Union and the United States. It might be thought that an arrangement that is so favourable to film production would receive unanimous support. On the contrary, it fuels controversy and is regularly criticised and even attacked. An example of this is producer Vincent Maraval’s claim at the end of 2012 that French actors are ‘overpaid’. This opinion piece had considerable repercussions because it called the funding system of French cinema into question. Its effects are still being felt today. This article will follow the thread of the discussion throughout 2013, a year that is a perfect case study because it presents an exceptional sequence of incidents and reactions around the question of film funding. Through their denunciation of the excesses linked to government assistance, criticism of the avance sur recettes (advance against earnings), rejection of the collective agreement, the fantasy of a cinema of ‘public servants’, and finger-pointing at films with low audiences, these reactions blurred the lines between supporters and opponents of the system. The author analyses the tensions and misunderstandings expressed in these debates, highlighting their often contradictory nature. She points out that these tensions have their origins in debates that significantly predate the very existence of cinema, because they follow in the footsteps of a traditional conflict in France between art and money. She above all stresses the fact that they have inherited a very old suspicion of any art form considered to be dependent on government support.

Max–min fair wireless energy transfer for multiple‐input multiple‐output wiretap channels

In this study, the authors study the max–min fairness for wireless energy transfer in a multiuser multiple-input multiple-output communication system with simultaneous wireless information and power transfer. In particular, they aim to maximise the minimum harvested energy among the multiple multi-antenna energy receivers while guaranteeing secure communication for multi-antenna information receiver. The dual use of artificial noise to facilitate both wireless energy transfer and secure communication is exploited in the authors’ proposed problem. Both scenarios of perfect and imperfect channel state information (CSI) known at the transmitter are considered. For the perfect CSI case, the formulated max–min energy harvesting (MM-EH) problem is non-convex and intractable. To circumvent it, an iterative optimisation algorithm based on Taylor series expansion is proposed. Then, they turn their attention to the imperfect CSI case, where a max–min robust energy harvesting (MMR-EH) problem is considered. Though the MMR-EH problem is more complicated than the MM-EH problem, they reveal that the iterative optimisation method can be extended to the solution of the former, wherein the S-procedure is introduced. Simulation results show the efficiency of their proposed solutions in terms of energy harvesting.

Using electric fields to induce patterning in leaky dielectric fluids in a rod-annular geometry

The stability and axisymmetric deformation of two immiscible, viscous, perfect or leaky dielectric fluids confined in the annulus between two concentric cylinders are studied in the presence of radial electric fields. The fields are set up by imposing a constant voltage potential difference between the inner and outer cylinders. We derive a set of equations for the interface in the long-wavelength approximation which retains the essential physics of the system and allows for interfacial deformations to be as large as the annular gap hence accounting for possible touchdown at the inner or outer electrode. The effects of the electric parameters are evaluated initially by performing a linear stability analysis which shows excellent agreement with the linear theory of the full axisymmetric problem in the appropriate long wavelength regime. The nonlinear interfacial dynamics are investigated by carrying out direct numerical simulations of the derived long wave models, both in the absence and presence of electric fields. For non-electrified thin layer flows (i.e. one of the layers thin relative to the other) the long-time dynamics agree with the lubrication approximation results found in literature. When the liquid layers have comparable thickness our results demonstrate the existence of both finite time and infinite time singularities (asymptotic touching solutions) in the system. It is shown that a two-side touching solution is possible for both the non-electrified and perfect dielectric cases, while only one-side touching is found in the case of leaky dielectric liquids, where the flattened interface shape resembles the pattern solutions found in literature. Meanwhile the finite-time singular solution agrees qualitatively with the experiments of~\cite{Reynolds1965}.

Investigating Orientational Defects in Energetic Material RDX Using First-Principles Calculations.

Orientational defects are molecular-scale point defects consisting of misaligned sterically trapped molecules. Such defects have been predicted in α-RDX using empirical force fields. These calculations indicate that their concentration should be higher than that of vacancies. In this study we confirm the stability of a family of four orientational defects in α-RDX using first-principles calculations and evaluate their formation energies and annealing barrier heights. The charge density distribution in the defective molecules is evaluated and it is shown that all four orientational defects exhibit some level of charge reduction at the midpoint of the N-N bond, which has been previously related to the sensitivity to initiation of the material. We also evaluate the vibrational spectrum of the crystal containing orientational defects and observe band splitting relative to the perfect crystal case. This may assist the experimental identification of such defects by Raman spectroscopy.

Noisy fiscal policy

This paper investigates the macroeconomic effects of fiscal policy in a setting in which private agents receive noisy signals about future shocks to government expenditures. We show how to empirically identify the relative weight of news and noise shocks to government spending and compute the level of noise for Canada, the UK and the US. We then investigate the quantitative implications of imperfect fiscal policy information using a medium-scale DSGE model. We find that when the government seeks to implement a persistent change in expected public spending, the existence of noise (as estimated using actual data) implies a sizable difference in fiscal multipliers compared to the perfect fiscal foresight case.

Investigating the change in surface acoustic wave velocity due to the change in adhesion of a SU-8 thin film using a SU-8/AlN/Si SAW sensor

This study investigates the change in surface acoustic wave (SAW) phase velocity due to the change in adhesion of a SU-8 thin film using an Aluminum Nitride (AlN)/Silicon (Si) SAW sensor. The variation in the stress field at the SU-8/AlN interface at different levels of SU-8 adhesion is also investigated and correlated to the change in SAW phase velocity. A theoretical model is developed to determine the change in wave dispersion profile due to the change in adhesion of the SU-8 film on the surface of the AlN/Si sensor. The interface of the SU-8/AlN layers is represented by a layer of massless springs with interface stiffness K (N/m3). The results illustrate that as the adhesion of the SU-8 film weakens on the surface of the AlN/Si SAW sensor the velocity dispersion profiles fluctuate. The calculated stress field at the SU-8/AlN interface also fluctuates because the weakened interface cannot sustain the increased stress due to the confinement of the wave near the interface. Therefore, the mode of wave propagation varies between the perfect bond case where the SU-8 layer is perfectly bonded to the AlN/Si surface and when the SU-8 is completely de-bonded. Four SAW sensor designs operating in the frequency range of 84–208MHz are developed to measure the shift in the center frequency values and the corresponding change in SAW phase velocities due to the change in adhesion of the SU-8 layer. The adhesion of the SU-8 film on the surface of the AlN/Si SAW sensor is changed by using different adhesion layers. The adhesion layers used are a gold film and an omnicoat coated gold film. Omnicoat is an adhesion promoter used to improve the adhesion of SU-8. The results illustrate that as the adhesion of the SU-8 film improves for the sensors with omnicoat the wave velocity shifts to a lower value. The wave velocity values are fitted with the wave dispersion profiles for different values of the interface spring stiffness K. The interface spring stiffness values for the SAW sensors with omnicoat coated gold and gold films are 8.1×109N/m3 and 7.95×109N/m3, respectively. The use of omnicoat improves the adhesion of the SU-8 film and corresponds to a higher interface spring stiffness value. The stress and displacement fields generated in the SU-8 layer for different values of the interface spring stiffness K are plotted. The results illustrate that as the adhesion of the SU-8 layer improves the stress transmitted to the SU-8 layer increases and the wave is more confined in the SU-8 layer, which justifies the drop in wave velocity since the Rayleigh wave velocity in SU-8 is much lower in comparison to AlN and Silicon; 1166, 5600, 5000m/s, respectively.

Thermal convection in inclined cylindrical containers

By means of direct numerical simulations (DNS) we investigate the effect of a tilt angle ${\it\beta}$, $0\leqslant {\it\beta}\leqslant {\rm\pi}/2$, of a Rayleigh–Bénard convection (RBC) cell of aspect ratio 1, on the Nusselt number $\mathit{Nu}$ and Reynolds number $\mathit{Re}$. The considered Rayleigh numbers $\mathit{Ra}$ range from $10^{6}$ to $10^{8}$, the Prandtl numbers range from 0.1 to 100 and the total number of the studied cases is 108. We show that the $\mathit{Nu}\,({\it\beta})/\mathit{Nu}(0)$ dependence is not universal and is strongly influenced by a combination of $\mathit{Ra}$ and $\mathit{Pr}$. Thus, with a small inclination ${\it\beta}$ of the RBC cell, the Nusselt number can decrease or increase, compared to that in the RBC case, for large and small $\mathit{Pr}$, respectively. A slight cell tilt may not only stabilize the plane of the large-scale circulation (LSC) but can also enforce an LSC for cases when the preferred state in the perfect RBC case is not an LSC but a more complicated multiple-roll state. Close to ${\it\beta}={\rm\pi}/2$, $\mathit{Nu}$ and $\mathit{Re}$ decrease with increasing ${\it\beta}$ in all considered cases. Generally, the $\mathit{Nu}({\it\beta})/\mathit{Nu}(0)$ dependence is a complicated, non-monotonic function of ${\it\beta}$.

Abstract TP91: Vessel Wall Imaging Demonstrates Aneurysm Wall Enhancement in Unruptured Posterior Communicating Artery Aneurysms With Oculomotor Nerve Palsy

Background: In ruptured aneurysms, vessel wall imaging (VWI) shows aneurysm wall enhancement, which may be caused by inflammation of the aneurysm wall. However, whether this inflammation is the cause or the result of aneurysm rupture remains unknown. In this study, we analyzed high-resolution VWI on posterior communicating artery (PComA) aneurysms, seeking to better understand aneurysm wall inflammation. Hypothesis: Oculomotor nerve palsy (ONP) is a warning sign of PComA aneurysm rupture. ONP results from compression of the oculomotor nerve and indicates aneurysm enlargement. Thus, PComA aneurysms with ONP are about to rupture, which makes them perfect cases to research aneurysm wall inflammation. If the inflammation of the aneurysm wall is the cause of aneurysm rupture, VWI may capture images of aneurysm wall enhancement before it ruptures. Methods: PComA aneurysm patients with ONP were examined using a Verio 3.0T scanner with a 12-channel head coil (Siemens Healthcare, Erlangen, Germany). Time-of-flight MRI angiography was performed to localize the aneurysm site. Then, a high-resolution T1-weighted black blood vessel wall sequence was obtained before and after intravenous administration of gadolinium. Each sequence was performed in the axial planes. Additional coronal planes or other planes were obtained if necessary. Patients with ruptured PComA aneurysms were also examined as a positive control, and patients with unruptured PComA aneurysms without ONP were examined as a negative control. Results: Ten patients with PComA aneurysm were examined. VWI of 3 patients with ONP showed aneurysm wall enhancement. Of these 3 patients, 2 were with post-orbital pain, and VWI showed complete enhancement of the aneurysm wall. VWI showed partial enhancement of the aneurysm wall in the other one patient without post-orbital pain. In the positive control group, complete wall enhancement was seen in all 3 ruptured PComA aneurysms (2 with ONP, 1 without ONP). In the negative control group of 4 cases, no aneurysm wall enhancement was seen. Conclusion: VWI demonstrated aneurysm wall enhancement in PComA aneurysms with ONP, which indicates that wall inflammation may occur before aneurysm rupture.

Territory and abiotic resources between 33 and 15.6 ka at Vale Boi (SW Portugal)

The environmental shifts during the Late Pleistocene had major influences in the landscape and, consequently, in the available resources. This had direct impact on human behavior and ecology, requiring people to constantly adjust to new economical conditions. In coastal areas, the retreat of the shoreline during the colder phases might have made available presently underwater raw material sources in the form of outcrops and gravels, eventually making it easier to gather lithic raw materials.In this paper, we present our preliminary results on the diachronic variability of raw materials in Vale Boi. Vale Boi is a coastal site, located 2.5 km from the present coastline, in the margins of a freshwater stream. The site has three different loci, all rich in lithics, fauna (including marine), bone tools, adornments, charcoal, and ochre, and evidence of continuous human occupation from c. 33 to 15.6 ka cal BP. This chronostratigraphic record makes it a perfect study case for the understanding of coastal populations' behavior and economy throughout the Upper Paleolithic.Our objective is to infer the territory of resources exploitation, landscape, and economic patterns. Raw material sources are usually fixed points on the landscape (in contrast to other resources such as fauna and flora) and, therefore, are one of the best ways of understanding how people moved in the landscape and, consequently, to infer past human behavior. We used a macroscopic approach in both the archaeological and the geological record in order to correlate sources and artifacts. Despite the absence of detailed quantitative data on each chert type, our results show that the hunter–gatherers who occupied Vale Boi during the Upper Paleolithic not only used several raw materials but also a variety of sources of the same raw material. This happened both diachronically and synchronically, suggesting that not only the complete sequence as well as each archaeological layer seem to have had a considerable economic complexity with the use of adjacent and distal sources. With this paper, we aim to present updated information on the variability of raw materials at Vale Boi, including the chert assemblages, along with new chert sources in order to establish a basis for a future detailed study on the raw material sourcing at the site.

机械发明时代的身体政治——短篇故事《被用光的人》的文化解读

在埃德加•爱伦•坡的短篇故事《被用光的人》中，外表俊美的名誉准将约翰•ABC•史密斯是个肉身几乎“被用光的人”，但是他在社交圈中却广受欢迎。在战争中被肢解后，史密斯将军不仅用最时尚的各种假体将自己组装成美男子，而且获得了一定的政治和社交资本。在特定的历史境况中，史密斯的身体已然成为一种文化符号，既反映出主流社会对科技产品的追捧，又折射出美国白人对待印第安人的立场。在坡的笔下，史密斯将军光鲜的外表和残缺不全的肉体形成了巨大反差，成了讽刺美国政坛自信自傲和技术崇拜的绝好范例。 In his short story “The Man That Was Used Up”, American classical writer Edgar Allan Poe presents a popular figure General John A. B. C. Smith who, after having been dismembered in the Indian War, not only reconstructs himself into an amazingly fine-looking man with the help of prosthetic devices, but also gains political and socializing capitals with his war experience. As a cultural code of the particular historical moment, his assembled body not only reveals the craze for technological products, but also reflects the way the white Americans viewed the frontier conflict. The huge discrepancy between Smith’s sublime body and his mutilated flesh actually becomes a perfect case with which Poe mocks the self-adulation and pompous arrogance of the political world and the fetishism of technological products in the American society.

Effect of Bolt-Hole Position Errors on the Strength of Bearing-Type Multi- Row Bolted Connection of FRP Composite Members

The aim of the study is to evaluate the effect of bolt-hole position errors on the strength of bearing-type multi-row bolted connections with a double-lap configuration of fiber reinforced polymer composite members. To simulate errors in positioning bolt-holes in the loading direction of connections, the statistical technique of sampling known as Latin hypercube sampling has been adopted in this study. In the Latin hypercube sampling, the distribution is obtained using the results of goodness of fit tests. It has been seen from the goodness of fit tests that the strength of the two- to fourrow bolted connections with steel cover plates and two-row bolted connection with FRP cover Plates can be modeled by using the normal distribution and the three and four-row bolted connections with FRP cover plates can be modeled by using the Weibull distribution with a significance level of 0.05. The strength of bolted connections is obtained by performing progressive damage analysis of the connections numerically. The statistical analyses show that the bolt-hole positioning errors have significant effect on the strength of the bolted connections, and that the strength can either increase or decrease with a larger probability to decrease. Connections with steel cover plates are more sensitive to bolt-hole position errors than those with FRP cover plates. Ninety five percent non-exceedance strength of the connection with FRP cover plates is about 85% of the connection with bolt positions perfectly aligned, that of the connection with steel cover plates is about 71% of the perfect bolt position case.