Enhanced‐image‐quality raster‐scanning chipset using feedback‐control actuation

Abstract— A new raster‐scanning chipset which provides enhanced projection performance is presented. The design is novel in that it combines electrostatic and electromagnetic actuation methods, along with a unique feedback‐control scheme to produce SVGA and WVGA projected images. A micromirror, the actuators, and drive electronics are integrated into a small, power‐efficient system, a scanning chipset, to increase its reliability and manufacturability.     

A bicriteria approach to minimize the total weighted number of tardy jobs with convex controllable processing times and assignable due dates

We study a single-machine scheduling problem in a flexible framework where both job processing times and due dates are decision variables to be determined by the scheduler. The model can also be applied for quoting delivery times when some parts of the jobs may be outsourced. We analyze the problem for two due date assignment methods and a convex resource consumption function. For each due date assignment method, we provide a bicriteria analysis where the first criterion is to minimize the total weighted number of tardy jobs plus due date assignment cost, and the second criterion is to minimize total weighted resource consumption. We consider four different models for treating the two criteria. Although the problem of minimizing a single integrated objective function can be solved in polynomial time, we prove that the three bicriteria models are NP\mathcal{NP}-hard for both due date assignment methods. We also present special cases, which frequently occur in practice, and in which all four models are polynomially solvable.     

Thermal polymerization of a brominated flame retardant in a glass‐fiber‐reinforced polypropylene—quantitative analysis

Pentabromobenzylacrylate (PBBA) is a possible candidate for use as a fire retardant (FR) in polypropylene (PP) composites. While PBBA imparts FR properties to the PP composite, it also affects adversely its mechanical properties. The FR may undergo thermal polymerization or grafting to the PP chains during processing. To study the effect of the different forms of FR (monomer, polymerized, or grafted) on composite properties, we have quantified the extent of FR polymerization and extent of grafting onto the PP chains. Fourier transform infrared microscopy was used in this work to determine the extent of polymerization and the spatial distribution of the FR. The latter was found to be homogeneous throughout the composite. Thermal polymerization of the FR during extrusion is varied mainly by the addition of an antioxidant. The grafting process of the FR onto PP depends on the degree of thermal polymerization, and therefore on the addition of antioxidant. The limiting value for grafting achieved at full polymerization is ～10% w/w. The grafted FR was found to have a significant effect on PP crystallinity, and hence it is expected to affect the mechanical properties as well. Bromine analysis indicates the FR has reacted with filler surfaces as well. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1506–1515, 2003     

A Proof of the Security of Quantum Key Distribution

We prove the security of theoretical quantum key distribution against the most general attacks which can be performed on the channel, by an eavesdropper who has unlimited computation abilities, and the full power allowed by the rules of classical and quantum physics. A key created that way can then be used to transmit secure messages such that their security is also unaffected in the future.     

On the generation of broad-band beams for a nondispersivetime-signal transmission

A novel aperture synthesis method is proposed for a broad-band beam (BB) generation, which supports a nondispersive time-signal transmission to a single observation plane. This plane, regarded here as the image plane (IP), is perpendicular to the axis of propagation and its location can be varied continuously from the near-field zone to the far-field zone. The spatial field of the BB at the IP can be shaped by modifying the classical spatial filtering synthesis techniques to construct a predetermined localized space-time (ST) field. The method characteristics, effectiveness, and simplicity, are demonstrated through two opposing analytic examples: Gaussian and rectangular source-field-distributions (SFD's)     

Environmental Policy Analysis, Peer Reviewed: Assessing the Environmental Movement's Attitudes Toward Risk Assessment

Risk Assessment.     

Effect of non-erupted third molars on roots of approximal teeth. A radiographic, clinical and histologic study

This study was undertaken to evaluate clinically and histologically root resorption in extracted human second molars in close proximity to non-erupted third molars. The control group consisted of extracted second molars that were proximal to fully erupted third molars. Eight out of the 11 teeth in the study group presented different degrees of radiographic root resorption, nine presented clinical resorption, and all 11 had histologic evidence of root resorption. In the control group, no signs of root resorption were seen radiographically or clinically. Histologically, limited sites of resorption were identified in all teeth, which were partially repaired by cellular cementum. Histologic observation of study specimens revealed root surface resorption in 10 out of the 11 teeth, one showing replacement resorption as well. Inflammatory resorption was observed in the three most advanced cases in the study group. Reparative cementum partially lining resorbed areas was evident in all teeth with surface resorption. Within the limits of this study, radiographic identification of distal root resorption of second molars in close proximity to non-erupted third molars appears reliable. The findings may support the hypothesis that the presence of a non-erupted third molar in close proximity to the distal root of the second results in root resorption.     

Electric-field-assisted proton-exchanged optical waveguides in lithium niobate

We describe the fabrication of a broad stripe optical wave-guide in z-cut lithium niobate by electric-field-assisted thermal proton exchange in a benzoic acid melt. Electric fields of 5 × 104V/m to 105V/m were laterally applied by means of in-contact gold thin-film electrodes 1 mm apart, producing an asymmetric depth across the width of the stripe. Similar vertical fields, applied across the thickness of the wafer, increased the stripe depth in the region of applied field. Refractive index profiles are given for both cases.     

Toward an explanation of cultural differences in in-group favoritism: The role of individual versus collective primacy.

Previous research conducted on a Western sample has shown that people are less apt to exhibit in-group favoritism when they perform well individually while their in-group performs poorly. The authors evaluated whether this finding would be moderated by the cultural dimension of individual–collective primacy, which refers to whether people give more weight to their personal interests rather than their in-group's interests when forced to choose between the two. The authors hypothesized that relative to their counterparts from the United States, participants from the People's Republic of China would have more of a collective-primacy orientation and therefore would exhibit more in-group favoritism when they performed well individually while their in-group performed poorly. The results supported the hypothesis. Implications for the literatures on in-group favoritism and cross-cultural differences are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Secure Distributed Key Generation for Discrete-Log Based Cryptosystems

A Distributed Key Generation (DKG) protocol is an essential component of threshold cryptosystems required to initialize the cryptosystem securely and generate its private and public keys. In the case of discrete-log-based (dlog-based) threshold signature schemes (ElGamal and its derivatives), the DKG protocol is further used in the distributed signature generation phase to generate one-time signature randomizers (r = g^k). In this paper we show that a widely used dlog-based DKG protocol suggested by Pedersen does not guarantee a uniformly random distribution of generated keys: we describe an efficient active attacker controlling a small number of parties which successfully biases the values of the generated keys away from uniform. We then present a new DKG protocol for the setting of dlog-based cryptosystems which we prove to satisfy the security requirements from DKG protocols and, in particular, it ensures a uniform distribution of the generated keys. The new protocol can be used as a secure replacement for the many applications of Pedersen's protocol. Motivated by the fact that the new DKG protocol incurs additional communication cost relative to Pedersen's original protocol, we investigate whether the latter can be used in specific applications which require relaxed security properties from the DKG protocol. We answer this question affirmatively by showing that Pedersen's protocol suffices for the secure implementation of certain threshold cryptosystems whose security can be reduced to the hardness of the discrete logarithm problem. In particular, we show Pedersen's DKG to be sufficient for the construction of a threshold Schnorr signature scheme. Finally, we observe an interesting trade-off between security (reductions), computation, and communication that arises when comparing Pedersen's DKG protocol with ours.