• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.256-256
• /
• 2006

The design and synthesis of novel biomolecular materials, based on mimicking the properties of molecules found in nature, is providing materials with unusual properties. Resilin serves as an energy storage material in insects and facilitates flight, jumping (in fleas, froghoppers etc) and sound production (cicadas, etc). Resilin is initially produced as a soluble protein and in its mature form is crosslinked through formation of dityrosine units into a very large insoluble polymer. In the present study, we have synthesized a recombinant form of resilin that can be photochemically cross-linked into a resilient, rubber-like biomaterial that may be suitable for spinal disc implants. This material is almost perfectly elastic and its fatigue lifetime in insects must be >500 million cycles.

• Wind and Structures
• /
• v.8 no.4
• /
• pp.295-307
• /
• 2005

The paper describes the work of the IAWE Working Group WBG - Reliability and Code Level, one of the International Codification Working Groups set up at ICWE10 in Copenhagen. The following topics are covered: sources of uncertainties in the design wind load, appropriate design target values for the exceedance probability of the design wind load for different structural classes with different consequences of a failure, yearly exceedance probability of the design wind speed and specification of the design aerodynamic coefficient for different design purposes. The recommendations from the working group are summarized at the end of the paper.

• International Journal of Concrete Structures and Materials
• /
• v.2 no.2
• /
• pp.107-113
• /
• 2008

The last 10 years have seen considerable growth in the use of proprietary and special repair cements for concrete pavements in the state of Oklahoma. Many of these products lend themselves to "fast track" construction techniques that allow reopening to traffic within 12 hours or less. These products achieve high early strengths by accelerating the Portland cement hydration process for both Type I and Type III cements. In this paper, the important features of a durable repair which include strength, compatibility and bond or adhesion are first discussed. Then the development, testing and field implementation of the aforementioned materials are discussed including the learning curve required to implement a repair system, not just install a new material. Some of the materials discussed, while expensive on a cost per unit basis, hold great promise for economical use on fast track project.

• Communications of Mathematical Education
• /
• v.18 no.2 s.19
• /
• pp.9-33
• /
• 2004

The purpose of this paper is to contribute to the dialogue about the notion of advanced mathematical thinking by offering an alternative characterization for this idea, namely advancing mathematical activity. We use the term advancing (versus advanced) because we emphasize the progression and evolution of students' reasoning in relation to their previous activity. We also use the term activity, rather than thinking. This shift in language reflects our characterization of progression in mathematical thinking as acts of participation in a variety of different socially or culturally situated mathematical practices. We emphasize for these practices the changing nature of student' mathematical activity and frame the process of progression in terms of multiple layers of horizontal and vertical mathematizing.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.1
• /
• pp.44.3-44.3
• /
• 2017

We introduce sample light curves of optical transients discovered by the KMTNet Supernoa Program, focusing on their early discoveries and rapid evolutions decoded in the high-cadence observations of the program. For some sources, we also show their spectra obtained either from rapid Target-of-Opportunity follow-up observations immediately after their discoveries or from regularly-scheduled observations. We expect the program to bring unprecedented insights into what is happening during early phases of various types of optical transients, centered on supernovae.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2006.11a
• /
• pp.74-79
• /
• 2006

General formula are presented for the maximum power available from the tidal head in a closed basin and from the tidal currents in a channel connecting two large bodies of water. In the latter case, the available energy cannot be estimated from the kinetic energy flux in the undisturbed state, but can be obtained from knowledge of the tidal head between the ends of the channel and the maximum volume flux in the undisturbed state. The results are supported by detailed calculations for Johnstone Strait, British Columbia, using a two-dimensional finite element model. The model also allows an extension to the case of multiple channels. More work is needed to allow for partial tidal fences which do not occupy the whole cross-section of a channel.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.6
• /
• pp.664-670
• /
• 2015

A four-times-VDD switch that supports high and low voltage mode operations is demonstrated in a generic 65 nm logic process. The proposed switch shows the robust operation for supply voltages ranging from VDD to $4{\times}VDD$. A cascaded voltage switch and a voltage doubler based charge pump generate the intermediate supply voltage levels required for the proposed high voltage switch. All the high voltage circuits developed in this work can be implemented using standard logic transistors without being subject to any voltage overstress.

• Journal of Forest and Environmental Science
• /
• v.31 no.1
• /
• pp.38-46
• /
• 2015

The stumpage price changes were calculated and analyzed from the data collected by Timber Mart-South from 1998 to 2007. We analyzed the relationship between pine sawtimber stumpage prices and timber sale characteristics using hedonic pricing method. Quadratic transformation was employed for sale size and contract length. Stumpage prices increased with sale size, contract length, bid sales, and the number of bidders. The presence of above average or excellent grade, market conditions, and logging conditions also are positively related to stumpage prices.

• Wind and Structures
• /
• v.16 no.3
• /
• pp.225-240
• /
• 2013

The wind-induced vibrations of the mast arm of cantilever traffic signal structures can lead to the fatigue failure of these structures. Wind tunnel tests were conducted on an aeroelastic model of this type of structure. Results of these experiments indicated that when the signals have backplates, vortex shedding causes large-amplitude vibrations that could lead to fatigue failure. Vibrations caused by galloping were only observed for one particular angle of attack with the signals having backplates. No evidence for galloping, previously thought to be the dominant cause of fatigue failures in these structures, was observed.

• Proceedings of the Korean Society for Bioinformatics Conference
• /
• 2000.11a
• /
• pp.28-31
• /
• 2000

We describe a hidden Markov model, HMMTIR, for general protein sequence based on the I-sites library of sequence-structure motifs. Unlike the linear HMMs used to model individual protein families, HMMSTR has a highly branched topology and captures recurrent local features of protein sequences and structures that transcend protein family boundaries. The model extends the I-sites library by describing the adjacencies of different sequence-structure motifs as observed in the database, and achieves a great reduction in parameters by representing overlapping motifs in a much more compact form. The HMM attributes a considerably higher probability to coding sequence than does an equivalent dipeptide model, predicts secondary structure with an accuracy of 74.6% and backbone torsion angles better than any previously reported method, and predicts the structural context of beta strands and turns with an accuracy that should be useful for tertiary structure prediction. HMMSTR has been incorporated into a public, fully-automated protein structure prediction server.