C/Si switch : Twofold sila‐substitution (C/Si exchange) in the RXR‐selective retinoids 4 a (SR11237) and 5 a leads to 4 b (disila‐SR11237) and 5 b , respectively. Chemistry and biology of the C/Si pairs are reported.
Private finance initiative (PFI) projects play an increasingly important role for both the United Kingdom government and the construction sector. It is still a relatively new form of procurement that requires a wide range of specialist advice during the bidding stage and in-depth knowledge of how the facility will perform in the long term. This paper investigates the level of participation in PFI projects in the United Kingdom, the opportunities available for the construction sector, the types of problems experienced, and the challenges for the future. It achieves this by analyzing the results of a questionnaire survey of a large number of client and construction organizations. The study finds that there is a wide gap in the level of PFI experience between client and construction organizations, affordability of PFI projects, and high bidding costs are key issues for client and construction organizations, respectively, and, given the nature of PFI projects, there is considerable scope for knowledge transfer both during the project and between different PFI projects. 相似文献
We present a reference model for finding (prima facie) evidence of discrimination in datasets of historical decision records
in socially sensitive tasks, including access to credit, mortgage, insurance, labor market and other benefits. We formalize
the process of direct and indirect discrimination discovery in a rule-based framework, by modelling protected-by-law groups,
such as minorities or disadvantaged segments, and contexts where discrimination occurs. Classification rules, extracted from
the historical records, allow for unveiling contexts of unlawful discrimination, where the degree of burden over protected-by-law
groups is evaluated by formalizing existing norms and regulations in terms of quantitative measures. The measures are defined
as functions of the contingency table of a classification rule, and their statistical significance is assessed, relying on
a large body of statistical inference methods for proportions. Key legal concepts and reasonings are then used to drive the
analysis on the set of classification rules, with the aim of discovering patterns of discrimination, either direct or indirect.
Analyses of affirmative action, favoritism and argumentation against discrimination allegations are also modelled in the proposed
framework. Finally, we present an implementation, called LP2DD, of the overall reference model that integrates induction,
through data mining classification rule extraction, and deduction, through a computational logic implementation of the analytical
tools. The LP2DD system is put at work on the analysis of a dataset of credit decision records. 相似文献
There are numerous applications where a variety of human and software participants interactively pursue a given task (play
a game, engage in a simulation, etc.). In this paper, we define a basic architecture for a distributed, interactive system
(DIS for short). We then formally define a mathematical construct called a DIS abstraction that provides a theoretical basis
for a software platform for building distributed interactive systems. Our framework provides a language for building multiagent
applications where each agent has its own behaviors and where the behavior of the multiagent application as a whole is governed
by one or more “master” agents. Agents in such a multiagent application may compete for resources, may attempt to take actions
based on incorrect beliefs, may attempt to take actions that conflict with actions being concurrently attempted by other agents,
and so on. Master agents mediate such conflicts. Our language for building agents (ordinary and master) depends critically
on a notion called a “generalized constraint” that we define. All agents attempt to optimize an objective function while satisfying
such generalized constraints that the agent is bound to preserve. We develop several algorithms to determine how an agent
satisfies its generalized constraints in response to events in the multiagent application. We experimentally evaluate these
algorithms in an attempt to understand their advantages and disadvantages.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
A program development system (PDS) should support a smooth transition between design, development, debugging, testing and final production of a software system. Man-machine interaction, though necessary, should not allow the user to modify the program or its execution state in an unstructured way; rather, disciplined interaction should be enforced by the PDS. After a review of the most desirable features of a PDS, the underlying philosophy of SIMPLE, a PDS which supports the development of Pascal programs, is introduced. The general structure of the SIMPLE system and the basic implementation choices are also discussed. 相似文献
The photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction has been a cornerstone of research in our laboratory for several years. In this Account we present an overview of the mechanistic exploration and rationalization of this photoinduced electron transfer reaction. We have investigated the mechanism and defined the synthetic scope and limitations by variations in reaction conditions and structural modification of the substrates. During our studies, we have come across several other pathways in competition with the photo-NOCAS reaction that dominate once specific conditions are altered. These alternative reactions are also discussed briefly. 相似文献
Spatio-temporal, geo-referenced datasets are growing rapidly, and will be more in the near future, due to both technological
and social/commercial reasons. From the data mining viewpoint, spatio-temporal trajectory data introduce new dimensions and,
correspondingly, novel issues in performing the analysis tasks. In this paper, we consider the clustering problem applied
to the trajectory data domain. In particular, we propose an adaptation of a density-based clustering algorithm to trajectory
data based on a simple notion of distance between trajectories. Then, a set of experiments on synthesized data is performed
in order to test the algorithm and to compare it with other standard clustering approaches. Finally, a new approach to the
trajectory clustering problem, called temporal focussing, is sketched, having the aim of exploiting the intrinsic semantics of the temporal dimension to improve the quality of trajectory
clustering.
The authors are members of the Pisa KDD Laboratory, a joint research initiative of ISTI-CNR and the University of Pisa: . 相似文献
The paper presents the development of segmented artificial crawlers endowed with passive hook-shaped frictional microstructures.
The goal is to find design rules for fabricating biomimetic, adaptable and mobile machines mimicking segmented animals with
hydrostatic skeleton, and intended to move effectively along unstructured substrates.
The paper describes the mechanical model, the design and the fabrication of a SMA-actuated segmented microrobot, whose locomotion
is inspired by the peristaltic motion of Annelids, and in particular of earthworms (Lumbricus Terrestris). Experimental locomotion performance are compared with theoretical performance predicted by a purposely developed friction
model -taking into account design parameters such as number of segments, body mass, special friction enhancement appendixes—and
with locomotion performance of real earthworms as presented in literature.
Experiments indicate that the maximum speed of the crawler prototype is 2.5 mm/s, and that 3-segment crawlers have almost
the same velocity as earthworms having the same weight (and about 330% their length), whereas 4-segment crawlers have the
same velocity, expressed as body lengths/s, as earthworms with the same mass (and about 270% their length).
Arianna Menciassi (MS, 1995; PhD, 1999) joined the CRIM Lab of the Scuola Superiore Sant’Anna (Pisa, Italy) as a Ph.D. student in Bioengineering
with a research program on the micromanipulation of mechanical and biological micro-objects. The main results of the activity
on micromanipulation were presented at the IEEE International Conference on Robotics & Automation (May 2001, Seoul) in a paper
titled “Force Feedback-based Microinstrument for Measuring Tissue Properties and Pulse in Microsurgery”, which won the “ICRA2001
Best Manipulation Paper Award”. In the year 2000, she was offered a position of Assistant Professor in Biomedical Robotics
at the Scuola Superiore Sant’Anna and in June 2006 she obtained a promotion to Associate Professor. Her main research interests
are in the field of biomedical microrobotics, biomimetics, microfabrication technologies, micromechatronics and microsystem
technologies. She is working on several European projects and international projects for the development of minimally invasive
instrumentation for medical applications and for the exploitation of micro- and nano-technologies in the medical field.
Samuele Gorini received his Laurea Degree in Mechanical Engineering (with honors) from the University of Pisa, Italy, in 2001. In 2005 he
obtained the Ph.D. in Microsystem Engineering with a thesis on locomotion methods and systems for miniaturised endoscopic
devices. Since 2000, he has been working at the CRIM Lab of the Scuola Superiore Sant’Anna in Pisa, Italy. His research interests
are in the field of biomedical robotics with a special focus on actuation technologies. Starting from the year 2004 he has
been president of Era Endoscopy S.r.l., a start-up company of Scuola Superiore Sant’Anna developing novel devices for endoscopy.
Dino Accoto (MS 1998, PhD 2002) is Assistant Professor of Biomedical Engineering at Scuola Sant’Anna (Pisa, Italy). He received the Laurea
degree in Mechanical Engineering from the University of Pisa (cum laude) in 1998, the diploma in Engineering from the Scuola
Sant’Anna (cum laude) in 1999 and the PhD degree from the Scuola Sant’Anna in 2002. From October 2001 to September 2002 he
has been visiting scholar at the RPL-Lab, Stanford University (Ca, USA). Since 2004 he cooperates with the Biomedical Robotics
& EMC Lab at Campus Bio-Medico University in Rome. His main research field is the modelling and development of small electromechanical
systems, with a special attention to multi-physics and multi-domain approaches. The research, often inspired by the analysis
of natural mechanisms, has been mainly applied to hybridizing microtechnologies, including microfluidics, and robotics. He
has co-authored more than 30 papers, appeared in international journals and conference proceedings.
Paolo Dario received his Dr. Eng. Degree in Mechanical Engineering from the University of Pisa, Italy, in 1977. He is currently a Professor
of Biomedical Robotics at the Scuola Superiore Sant’Anna in Pisa.. He also teaches courses at the School of Engineering of
the University of Pisa and at the Campus Biomedico University in Rome. He has been Visiting Professor at Brown University,
Providence, RI, USA, at the Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland, at Waseda University,
Tokyo, Japan, at the College de France, Paris, and at the Ecole Normale Superieure de Cachan, France. He was the founder of
the ARTS (Advanced Robotics Technologies and Systems) Laboratory and is currently the Co-ordinator of the CRIM (Center for
the Research in Microengineering) Laboratory of the Scuola Superiore Sant’Anna, where he supervises a team of about 70 researchers
and Ph.D. students. His main research interests are in the fields of medical robotics, bio-robotics, mechatronics and micro/nanoengineering,
and specifically in sensors and actuators for the above applications, and in robotics for rehabilitation. He is the coordinator
of many national and European projects, the editor of two books on the subject of robotics, and the author of more than 200
scientific papers (75 on ISI journals). He is Editor-in-Chief, Associate Editor and member of the Editorial Board of many
international journals. Prof. Dario has served as President of the IEEE Robotics and Automation Society in the years 2002–2003.
He has been the General Chair of the IEEE RAS-EMBS BioRob’06 Conference and he is the General Co-Chair of ICRA 2007 Conference.
Prof. Dario is an IEEE Fellow, a Fellow of the European Society on Medical and Biological Engineering, and a recipient of
many honors and awards, such as the Joseph Engelberger Award. He is also a member of the Board of the International Foundation
of Robotics Research (IFRR). 相似文献
The purpose of this research study is to study the sustainable manufacturing practices across industrial sectors and to identify
the critical factors for its success implementation. In spite of the fact that sustainable manufacturing has been frequently
promoted as a means of improving business competitiveness, small empirical evidence exists in the literature validating its
positive link with organizational performance. Sustainable manufacturing practices enable the manufacturing organizations
to survive in the competitive environment. For this purpose, empirical data are collected to measure the sustainable manufacturing
practices prevailing across different industries located in Tamil Nadu, India. Structural equation modeling (SEM) technique
is used to build the measurement and structural models. After that, statistical estimates are used to validate the built model.
The data analysis enables the acceptance or rejection of the hypothesis that has been stated on the basis of structural model.
The results show the correlation between sustainable manufacturing practices and organizational performance among the industries
being surveyed. 相似文献
3YSZ specimens with variable open porosity (1–57%) were fabricated, and the stiffness, strength and fracture properties (fracture toughness and R-curve) were measured to investigate their potential use as support structures for solid oxide fuel or electrolysis cells. The ball-on-ring test was used to characterize Young's modulus and Weibull strength. The variation of fracture toughness with porosity was investigated and modelled using the results from fracture mechanical testing. A distinct R-curve behaviour was observed in dense 3YSZ specimens, in samples with a porosity around 15% and in some of the highly porous samples (porosities ~45%) reflecting a transformation toughening in the material. For the most porous samples, the “R-curve behaviour” disappeared and subcritical crack growth was observed. The studies indicate that even highly porous 3YSZ structures (porosities exceeding 40%) are feasible supports for SOFC/SOECs from a mechanical point of view. 相似文献