Effect of present technology on airship capabilities

The effect is presented of updating past airship designs using current materials and propulsion systems to determine new airship performance and productivity capabilities. New materials and power plants permit reductions in the empty weights and increases in the useful load capabilities of past airship designs. The increased useful load capability results in increased productivity for a given range, i.e., either increased payload at the same operating speed or increased operating speed for the same payload weight or combinations of both. Estimated investment costs and operating costs are presented to indicate the significant cost parameters in estimating transportation costs of payloads in cents per ton mile. Investment costs are presented considering production lots of 1, 10 and 100 units. Operating costs are presented considering flight speeds and ranges

The graceful exit in pre-big bang string cosmology

We re-examine the graceful exit problem in the pre-big bang scenario of string cosmology, by considering the most general time-dependent classical correction to the Lagrangian with up to four derivatives. By including possible forms for quantum loop corrections we examine the allowed region of parameter space for the coupling constants which enable our solutions to link smoothly the two asymptotic low-energy branches of the pre-big bang scenario, and observe that these solutions can satisfy recently proposed entropic bounds on viable singularity free cosmologies.Comment: 14 pages, 6 figures, JHEP class. Added new section on the classical correction and reference

The impact of water on free-falling bodies

Report discussed measures to cushion impact on body falling into water. Heavy loads are generated by impact and by pressures of water cavity collapsing onto the body

Human persistence

Both advocates and opponents of the animalist view that we are fundamentally biological organisms have typically assumed that animalism is incompatible with intuitive verdicts about cerebrum isolation and transplantation. It is argued here that this assumption is a mistake. Animalism, developed in a natural way, in fact strongly supports these intuitive verdicts. The availability of this attractive resolution of a central puzzle in the personal identity debate has been obscured by a range of factors, including the prevalence in contemporary metaphysics of a certain conception of the nature of organisms. I end by explaining how the animalist can use intuitive verdicts, usually thought to present a difficulty for the view, as positive evidence for claims about the persistence conditions of the relevant kind of organism

Reflexivity, Realism, and Consciousness

The author raises a puzzle about the compatibility of the two features which, according to Ayers, jointly characterize paradigmatic cases of seeing, viz. ‘perspicuity’ and ‘immediacy’. In Section 1, the author explains why Ayers’s explanation of these two features suggests an inconsistent combination of reflexivity and realism about sense experience. Some of Ayers’s comments about our awareness of causation suggest a way of giving up on reflexivity. In Section 2, the author uses a thought-experiment to support the view that realism rather than reflexivity ought to be given up. In Section 3, the author gives a further reason for Ayers to take this option: it furnishes a response to a troublesome challenge concerning the epistemic significance of consciousness, a challenge which Ayers himself anticipates at the end of Chapter 2 of Knowing and Seeing but does not fully resolve

Genetic algorithms: a pragmatic, non-parametric approach to exploratory analysis of questionnaires in educational research

Data from a survey to determine student attitudes to their courses are used as an example to show how genetic algorithms can be used in the analysis of questionnaire data. Genetic algorithms provide a means of generating logical rules which predict one variable in a data set by relating it to others. This paper explains the principle underlying genetic algorithms and gives a non-mathematical description of the means by which rules are generated. A commercially available computer program is used to apply genetic algorithms to the survey data. The results are discussed

Optimum design of high speed prop rotors including the coupling of performance, aeroelastic stability and structures

An optimization procedure is developed for the design of high speed prop-rotors to be used in civil tiltrotor applications. The goal is to couple aerodynamic performance, aeroelastic stability, and structural design requirements inside a closed-loop optimization procedure. The objective is to minimize the gross weight and maximize the propulsive efficiency in high speed cruise. Constraints are imposed on the rotor aeroelastic stability in both hover and cruise and rotor figure of merit in hover. Both structural and aerodynamic design variables are used

Out of Bounds: Commerce Clause Protection from State Antitrust Statutes for Regional Athletic Conferences

Collegiate athletic conferences generate billions of dollars annually. With conferences competing for $300 million plus television contracts, it has become increasingly important that conferences align themselves with the highest quality institutions possible. As a result, individual institutions have shifted from one conference to another with hopes of cashing in on higher revenue opportunities. The regional athletic conferences that govern these individual institutions are different from most commercial actors because their very nature requires that they be regulated on a national/regional level if they are to exist at all. Each member of a conference voluntarily agrees to be bound by the conference’s constitution and by-laws. As such, it is imperative that the by-laws and rules be applied uniformly across the conference in order to have any possibility of functioning effectively. However, subjecting regional athletic conferences to state antitrust laws imposes an excessive burden on the conference without a corresponding local benefit. If regional athletic conferences were subject to state antitrust claims, the member institution’s state with the strictest antitrust laws would effectively regulate the activities of the member institutions in other states. In effect, a conference would be stripped of its ability to freely adopt and enforce its own procedural regulations. To avoid these burdens, regional athletic conferences should be able to seek protection by invoking the dormant side of the Commerce Clause in the face of state antitrust claims. The trajectory of case law on the subject suggests that it is logical that regional athletic conferences should enjoy the protection of the dormant Commerce Clause

MDCC: Multi-Data Center Consistency

Replicating data across multiple data centers not only allows moving the data closer to the user and, thus, reduces latency for applications, but also increases the availability in the event of a data center failure. Therefore, it is not surprising that companies like Google, Yahoo, and Netflix already replicate user data across geographically different regions. However, replication across data centers is expensive. Inter-data center network delays are in the hundreds of milliseconds and vary significantly. Synchronous wide-area replication is therefore considered to be unfeasible with strong consistency and current solutions either settle for asynchronous replication which implies the risk of losing data in the event of failures, restrict consistency to small partitions, or give up consistency entirely. With MDCC (Multi-Data Center Consistency), we describe the first optimistic commit protocol, that does not require a master or partitioning, and is strongly consistent at a cost similar to eventually consistent protocols. MDCC can commit transactions in a single round-trip across data centers in the normal operational case. We further propose a new programming model which empowers the application developer to handle longer and unpredictable latencies caused by inter-data center communication. Our evaluation using the TPC-W benchmark with MDCC deployed across 5 geographically diverse data centers shows that MDCC is able to achieve throughput and latency similar to eventually consistent quorum protocols and that MDCC is able to sustain a data center outage without a significant impact on response times while guaranteeing strong consistency