Remote booting in a hostile world: to whom am I speaking? [Computer security]

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”Today's networked computer systems are very vulnerable to attack: terminal software, like that used by the X Window System, is frequently passed across a network, and a trojan horse can easily be inserted while it is in transit. Many other software products, including operating systems, load parts of themselves from a server across a network. Although users may be confident that their workstation is physically secure, some part of the network to which they are attached almost certainly is not secure. Most proposals that recommend cryptographic means to protect remotely loaded software also eliminate the advantages of remote loading-for example, ease of reconfiguration, upgrade distribution, and maintenance. For this reason, they have largely been abandoned before finding their way into commercial products. The article shows that, contrary to intuition, it is no more difficult to protect a workstation that loads its software across an insecure network than to protect a stand-alone workstation. In contrast to prevailing practice, the authors make essential use of a collision-rich hash function to ensure that an exhaustive off-line search by the opponent will produce not one, but many candidate pass words. This strategy forces the opponent into an open, on-line guessing attack and offers the user a defensive strategy unavailable in the case of an off-line attack.Peer reviewe

Geometric approach to Fletcher's ideal penalty function

Original article can be found at: www.springerlink.com Copyright Springer. [Originally produced as UH Technical Report 280, 1993]In this note, we derive a geometric formulation of an ideal penalty function for equality constrained problems. This differentiable penalty function requires no parameter estimation or adjustment, has numerical conditioning similar to that of the target function from which it is constructed, and also has the desirable property that the strict second-order constrained minima of the target function are precisely those strict second-order unconstrained minima of the penalty function which satisfy the constraints. Such a penalty function can be used to establish termination properties for algorithms which avoid ill-conditioned steps. Numerical values for the penalty function and its derivatives can be calculated efficiently using automatic differentiation techniques.Peer reviewe

Lessons Learned in Designing Active Learning Modules for the STEM Classroom

For students to become real partners in their education, they must shift from a model of passive absorption of knowledge to one of active participation in constructing knowledge. To encourage this shift, I have designed a variety of active learning modules for my introductory chemistry classes, from short participation polls to full-length case studies. When well-implemented, in-class activities can be a valuable experience for students to practice applying their knowledge with instructor guidance. In this report, I will share both successes and challenges encountered in designing student-friendly active learning modules in an introductory science course

Alien Registration- Christianson, Louise M. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/24416/thumbnail.jp

More security or less insecurity

We depart from the conventional quest for ‘Completely Secure Systems’ and ask ‘How can we be more Secure’. We draw heavily from the evolution of the Theory of Justice and the arguments against the institutional approach to Justice. Central to our argument is the identification of redressable insecurity, or weak links. Our contention is that secure systems engineering is not really about building perfectly secure systems but about redressing manifest insecurities.Final Accepted Versio

Globalization of Pantoja's optimal control algorithm

© 2002 Springer Science+Business Media New York. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/978-1-4613-0075-5_13In 1983 Pantoja described a stagewise construction of the Newton direction for a general class of discrete time optimal control problems. His algorithm incurs amazingly low overheads: the cost (measured in target function evaluations) is independent of the number of discrete time-steps. The algorithm can be modified to verify that the Hessian contains no eigen values less than a postulated quantity, and to produce an appropriate descent direction in the case where the Hessian fails to be positive definite and global convergence becomes an issue. Coleman and Liao have proposed a specific damping strategy in this context. Here we describe how Automatic Differentiation can be used to implement Pantoja’s algorithm, and we briefly consider some alternative globalization strategies, within which AD techniques can be further deployed.Final Accepted Versio

Inelastic neutron scattering study on the resonance mode in an optimally doped superconductor LaFeAsO0.92_{0.92}F0.08_{0.08}

An optimally doped iron-based superconductor LaFeAsO$_{0.92}$F$_{0.08}$ with $T_c = 29$ K has been studied by inelastic powder neutron scattering. The magnetic excitation at $Q=1.15$ \AA$^{-1}$ is enhanced below $T_c$, leading to a peak at $E_{res}\sim13$ meV as the resonance mode, in addition to the formation of a gap at low energy below the crossover energy $\Delta_{c}\sim10 meV$. The peak energy at $Q=1.15$ \AA$^{-1}$ corresponds to $5.2 k_B T_c$ in good agreement with the other values of resonance mode observed in the various iron-based superconductors, even in the high-$T_c$ cuprates. Although the phonon density of states has a peak at the same energy as the resonance mode in the present superconductor, the $Q$-dependence is consistent with the resonance being of predominately magnetic origin.Comment: 4 pages, 5 Postscript figure

Network Analysis of Affordable Housing Organizations in Polk County

This study provides a picture of the institutional network engaged in the provision of affordable housing in Polk County, what we have termed the Polk County Affordable Housing Network (PCAH Network). It analyzes the web of relationships that structure the network including the number of connections, strength of connections, and degree of influence within the network. Understanding the structure of the PCAH Network and the relationships between the actors will enable funders, decision-‐‐makers, and others engaged in the issue to identify existing knowledge gaps and barriers to innovation and to improve how organizations work together to provide affordable housing in Polk County

Housing Barriers and Housing Strategies among Low Income Households in Polk County, Iowa

Traditional housing needs assessments rely on quantitative analyses focused on issues of supply and demand. These studies are not intended to look at the fine-grained details of how individual households manage the trade-offs created by limited resources. This study seeks to provide a more nuanced understanding of the housing needs of low income households in Polk County, including the barriers they face while trying to access affordable housing and the strategies they use in their efforts to remain housed within a context of economic constraints.This qualitative element of the Polk County Housing Needs Assessment study asked two questions: (1) What barriers do households in need of affordable housing face when trying to access affordable housing? And (2) What housing strategies are utilized by income households in Polk County? The findings reported in this study are based on nine in-depth interviews where respondents recounted their personal housing histories and housing aspirations