• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4159-4164
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• 2012

This paper presents a chaotic circuit with voltage controllability for secure communication applications. The proposed circuit which has two control voltages consists of the nonlinear function block(NFB) with three MOS transistors, one source follower and non-overlapping two-phase clock generator for sample and hold. By SPICE simulation, chaotic dynamics such as time waveform, frequency analysis and bifurcations were analyzed. SPICE results showed that proposed circuit can make various chaotic signals by control voltage.

• Journal of Multimedia Information System
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• v.2 no.3
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• pp.255-262
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• 2015

The modern manufacturing systems and technologies produce products that are more accurate day by day. This can be reached mainly by improvement the manufacturing process with at the same time restricting more and more the quality specifications and reducing the uncertainty in part. The main objective an industry becomes to lower the part's variability, since the less variability - the better is product. One of the part of this task is measuring the object's uncertainty. The main purpose of this study is to understand the application of bootstrap method for uncertainty evaluation. Bootstrap method is a collection of sample re-use techniques designed to estimate standard errors and confidence intervals. In the case study a surface of an automobile engine block - (Top view side) is measured by Coordinate Measuring Machine (CMM) and analyzed for uncertainty using Geometric Least Squares in complex with bootstrap method. The designed experiment is composed by three similar measurements (the same features in unique reference system), but with different points (5, 10, 20) concentration at each level. Then each cloud of points was independently analyzed by means of non-linear Least Squares, after estimated results have been reported. A MatLAB software tool used to generate new samples using bootstrap function. The results of the designed experiment are summarized and show that the bootstrap method provides the possibility to evaluate the uncertainty without repeating the Coordinate Measuring Machine (CMM) measurements many times, i.e. potentially can reduce the measuring time.

• Journal of Communications and Networks
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• v.12 no.4
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• pp.334-345
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• 2010

In this paper, we study optimal tradeoffs of achievable throughput versus consumed power in wireless ad-hoc networks formed by a collection of multiple antenna nodes. Relying on adaptive modulation and/or dynamic channel coding rate allocation techniques for multiple antenna systems, we examine the maximization of throughput under power constraints as well as the minimization of transmission power under throughput constraints. In our examination, we also consider the impacts of enforcing quality of service requirements expressed in the form of channel coding block loss constraints. In order to properly model temporally correlated loss observed in fading wireless channels, we propose the use of finite-state Markov chains. Details of fading statistics of signal-to-interference-noise ratio, an important indicator of transmission quality, are presented. Further, we objectively inspect complexity versus accuracy tradeoff of solving our proposed optimization problems at a global as oppose to a local topology level. Our numerical simulations profile and compare the performance of a variety of scenarios for a number of sample network topologies.

• 지반과기술
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• v.3 no.3
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• pp.15-22
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• 2006

The optimum blasting pattern to excavate a quarry efficiently and economically can be determined based on the minimum production cost, which is generally estimated according to rock fragmentation. Therefore, it is a critical problem to predict fragment size distribution of blasted rocks over an entire quarry. By comparing various prediction models, it can be ascertained that the result obtained from Kuz-Ram model relatively coincides with that of field measurements. Kuz-Ram model uses the concept of rock factor to signify conditions of rock mass such as block size, rock jointing, strength and others. For the evaluation of total production cost, it is imperative to estimate 3-D spatial distribution of rock factor for the entire quarry. In this study, a sequential indicator simulation technique is adopted for estimation of spatial distribution of rock factor due to its higher reproducibility of spatial variability and distribution models than Kriging methods. Further, this can reduce the uncertainty of predictor using distribution information of sample data. The entire quarry is classified into three types of rock mass and optimum blasting pattern is proposed for each type based on 3-D spatial distribution of rock factor. In addition, plane maps of rock factor distribution for each ground level are provided to estimate production costs for each process and to make a plan for an optimum blasting pattern.

• Journal of Communications and Networks
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• v.15 no.5
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• pp.514-526
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• 2013

With a long sensing period, the inter-frame spectrum sensing in IEEE 802.22 standard is vulnerable to the effect of the traffic of the primary user (PU). In this article, we address the two degrading factors that affect the inter-frame sensing performance with respect to the random arrival/leaving of the PU traffic. They are the noise-only samples under the random arrival traffic, and the PU-signal-contained samples under the random leaving traffic. We propose the model in which the intra-frame sensing cooperates with the inter-frame one, and the inter-frame sensing uses the time-of-arrival (ToA), and time-of-leave (ToL) detectors to reduce the two degrading factors in the inter-frame sensing time. These ToA and ToL detectors are used to search for the sample which contains either the ToA or ToL of the PU traffic, respectively, which allows the partial cancelation of the unnecessary samples. At the final stage, the remaining samples are input into a primary user detector, which is based on the energy detection scheme, to determine the status of PU traffic in the inter-frame sensing time. The analysis and the simulation results show that the proposed scheme enhances the spectrum-sensing performance compared to the conventional counter-part.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.283-290
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• 2004

In this paper, a low-power structure for 512 tap FIR filter in MPEG audio algorithm is proposed. By using CSD(Canonic Signed Digit) form filter coefficients and maximum sharing of input signal sample, it is shown that the number of adders of proposed structure can be minimized. To minimize the number of adders, the proposed structure utilizes the 4 steps of sharing, i.e., common input sharing, linear phase symmetric filter coefficient sharing, block sharing for common input, and common sub-expression sharing. Through Verilog-HDL coding, it is shown that reduction rates in the implementation area and relative power consumption of the proposed structure are 60.3% and 93.9% respectively, comparison to those of the conventional multiplier structure.

• Journal of Korean Society of Rural Planning
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• v.18 no.1
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• pp.17-28
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• 2012

Functional mismatch and thought and plan-less material use of recently built boundary barriers in rural areas should greatly degrade their amenity value as one of linear villagescapes, but, their present state-of-art basically necessary for problem-solving had never surveyed up to now. From this point of view, this study tried to investigate present stock quantities and qualities of boundary barriers in rural areas by sample studies on 21 case villages(7 types ${\times}$ 3 cases) and comparative analysis between the planned or improved and nots. Wall type was absolutely dominated in the structural terms, of which more than half was used cement block as building material and, therefore, grey-colored. More than half of total barrier length were fully shielded, while relatively partially shielded in the mountainous villages in open space and 'Cultural villages' with closed housing structures. Free standing style of barriers was shown along over two thirds of their total length, although not more than half in planned reclaimed villages. Especially, because of one-sided wall type structure, mismatched over-shieldness and poorer maintenance condition of the boundary barriers in peri-urban villages, there should be provided with very intensive improvement efforts for amenity barriers.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.1-1
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• 2000

The infinite layer compound $ACuO_2$, (A-Alkaline earth) consists of infinite stacking of $CuO_2$ planes separated only by alkaline earth ions. This compound attracted much attention because it contains only key ingredient of all cuprate high temperature superconductor; $CuO_2$ plane with controllable carrier concentration without charge reservoir block. High pressure synthesis method has been found to be preferable for this system due to its ability of doping various lanthanide ion into A site with larger superconducting volume fraction. But rigorous study on this rudimentary compound has been hindered by insufficient quality of sample. Especially superconductlng volume fraction was often too small to identify its origin. In this presentation, we report high pressure synthesis of $Sr_{0.9}Ln_{0.1}CuO_2$ (Ln=La, Sm). By controlling the heating temperature precisely during high pressure synthesis we could have superconductors with quite high superconducting volume fraction for this compound. The magnetic properties of the graln aligned samples show very different behavior compared to the cuprate high temperature superconductors. Details will be discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.06b
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• pp.19-44
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• 1993

The purpose of this paper is to study the design and the construction for the most economic and safe slope stability analysis. The approach to the purpose Iies in analyzing the characteristic on direction and distance by the sample value for the geotechnical parameters using the semi-variogram concept. Based on the result, we derive the Kriging system equation from the stochastical concept and solve the equation to find the weighting factor which is applied both the point estimation and the block estimation in the particular position. Comparing and analyzing the various methods. we find the best reliability, which is more accurate than any other.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.383-391
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• 2014

Biotin-S-S-Phosphine was designed and synthesized as a potential tool for a proteomic study of O-GlcNAcmodified proteins. This reagent features a disulfide linker between a triarylphosphine moiety, which allows selective conjugation to azide-containing proteins, and a biotin moiety that can allow easy isolation through its strong affinity toward avidin-coated solid beads. The disulfide linkage within this reagent can allow the easy release of the bound molecules of interest, which is difficult to achieve when a biotin:avidin pair is used alone, by reducing the disulfide bond of the reagent with DTT. Preliminary in vitro biological assays with azidelabeled and unlabeled cell lysates and a pure protein Nup62 showed that the Biotin-S-S-Phosphine reagent is highly reactive toward the free thiol groups of proteins. When a molecular tool with a disulfide linker is applied to the enrichment of the molecules of interest from other species, it is important to block the free-thiols of the sample using exhaustive alkylation prior to the Staudinger ligation reactions to restore the bioorthogonal nature of this reaction.