• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.237-249
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• 2014

Deposition of amyloid-${\beta}$ ($A{\beta}$) proteins is the conventional pathological hallmark of Alzheimer's disease (AD). The $A{\beta}$ protein formed from the amyloid precursor protein is predominated by the 40 residue protein ($A{\beta}40$) and by the 42 residue protein ($A{\beta}42$). While $A{\beta}40$ and $A{\beta}42$ differ in only two amino acid residues at the C-terminal end, $A{\beta}42$ is much more prone to aggregate and exhibits more neurotoxicity than $A{\beta}40$. Here, we investigate the molecular origin of the difference in the aggregation propensity of these two proteins by performing fully atomistic, explicit-water molecular dynamics simulations. Then, it is followed by the solvation thermodynamic analysis based on the integral-equation theory of liquids. We find that $A{\beta}42$ displays higher tendency to adopt ${\beta}$-sheet conformations than $A{\beta}40$, which would consequently facilitate the conversion to the ${\beta}$-sheet rich fibril structure. Furthermore, the solvation thermodynamic analysis on the simulated protein conformations indicates that $A{\beta}42$ is more hydrophobic than $A{\beta}40$, implying that the surrounding water imparts a larger thermodynamic driving force for the self-assembly of $A{\beta}42$. Taken together, our results provide structural and thermodynamic grounds on why $A{\beta}42$ is more aggregation-prone than $A{\beta}40$ in aqueous environments.

• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.131-135
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• 1995

In winter, most of the energy for a greenhouse crop is supplied during the night. Since watermelon is grown under high night temperature, the experiments were set up to investigate night temperature influence on watermelon in order to obtain the best economic output. Day temperatures ranged from $25^{\circ}C$ and 3$0^{\circ}C$ ; night temperatures ranged from 2$0^{\circ}C$ to 3$0^{\circ}C$ at 5$^{\circ}C$ interval. Two cultivars of watermelon(Citrullus vulgaris S. ‘Binna’ and ‘Kamro’) treated with 30/3$0^{\circ}C$ yielded maximum leaf areas, flowers and leaf numbers. 30(14h)/25(10h)$^{\circ}C$ or 30(12h)/25(12h)$^{\circ}C$ grown plants had higher germination ratio and more dry weight and chlorophyll than those of 30/3$0^{\circ}C$ which were the highest temperature integral. Although 25/$25^{\circ}C$ and 30/2$0^{\circ}C$ regime are same average temperature, the growth of watermelons at 30/2$0^{\circ}C$ was significantly higher than 25/$25^{\circ}C$. ‘Binna’ was growing more than ‘Kamro’ at the same temperature. Leaf area ratio(LAR) was reduced with increasing DIF temperature from 30/3$0^{\circ}C$ to 30/2$0^{\circ}C$, but leaf weight ratio(LWR) was increased.

• KIEE International Transaction on Systems and Control
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• v.2D no.2
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• pp.78-91
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• 2002

In the thermal power plant, there are six manipulated variables: main steam flow, feedwater flow, fuel flow, air flow, spray flow, and gas recirculation flow. There are five controlled variables: generator output, main steam pressure, main steam temperature, exhaust gas density, and reheater steam temperature. Therefore, the thermal power plant control system is a multinput and output system. In the control system, the main steam temperature is typically regulated by the fuel flow rate and the spray flow rate, and the reheater steam temperature is regulated by the gas recirculation flow rate. However, strict control of the steam temperature must be maintained to avoid thermal stress. Maintaining the steam temperature can be difficult due to heating value variation to the fuel source, time delay changes in the main steam temperature versus changes in fuel flow rate, difficulty of control of the main steam temperature control and the reheater steam temperature control system owing to the dynamic response characteristics of changes in steam temperature and the reheater steam temperature, and the fluctuation of inner fluid water and steam flow rates during the load-following operation. Up to the present time, the Proportional-Integral-Derivative Controller has been used to operate this system. However, it is very difficult to achieve an optimal PID gain with no experience, since the gain of the PID controller has to be manually tuned by trial and error. This paper focuses on the characteristic comparison of the PID controller and the modified 2-DOF PID Controller (Two-Degrees-Freedom Proportional-Integral-Derivative) on the DCS (Distributed Control System). The method is to design an optimal controller that can be operated on the thermal generating plant in Seoul, Korea. The modified 2-DOF PID controller is designed to enable parameters to fit into the thermal plant during disturbances. To attain an optimal control method, transfer function and operating data from start-up, running, and stop procedures of the thermal plant have been acquired. Through this research, the stable range of a 2-DOF parameter for only this system could be found for the start-up procedure and this parameter could be used for the tuning problem. Also, this paper addressed whether an intelligent tuning method based on immune network algorithms can be used effectively in tuning these controllers.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.74-74
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• 2010

One-dimensional nanosturctures such as nanowires and nanotube have been mainly proposed as important components of nano-electronic devices and are expected to play an integral part in design and construction of these devices. Silicon carbide(SiC) is one of a promising wide bandgap semiconductor that exhibits extraordinary properties, such as higher thermal conductivity, mechanical and chemical stability than silicon. Therefore, the synthesis of SiC-based nanowires(NWs) open a possibility for developing a potential application in nano-electronic devices which have to work under harsh environment. In this study, one-dimensional nanowires(NWs) of cubic phase silicon carbide($\beta$-SiC) were efficiently produced by thermal chemical vapor deposition(T-CVD) synthesis of mixtures containing Si powders and hydrocarbon in a alumina boat about $T\;=\;1400^{\circ}C$ SEM images are shown that the temperature below $1300^{\circ}C$ is not enough to synthesis the SiC NWs due to insufficient thermal energy for melting of Si Powder and decomposition of methane gas. However, the SiC NWs are produced over $1300^{\circ}C$ and the most efficient temperature for growth of SiC NWs is about $1400^{\circ}C$ with an average diameter range between 50 ~ 150 nm. Raman spectra revealed the crystal form of the synthesized SiC NWs is a cubic phase. Two distinct peaks at 795 and $970\;cm^{-1}$ over $1400^{\circ}C$ represent the TO and LO mode of the bulk $\beta$-SiC, respectively. In XRD spectra, this result was also verified with the strongest (111) peaks at $2{\theta}=35.7^{\circ}$, which is very close to (111) plane peak position of 3C-SiC over $1400 ^{\circ}C$ TEM images are represented to two typical $\beta$-SiC NWs structures. One is shown the defect-free $\beta$-SiC nanowire with a (111) interplane distance with 0.25 nm, and the other is the stacking-faulted $\beta$-SiC nanowire. Two SiC nanowires are covered with $SiO_2$ layer with a thickness of less 2 nm. Moreover, by changing the flow rate of methane gas, the 300 sccm is the optimal condition for synthesis of a large amount of $\beta$-SiC NWs.

• Journal of Positioning, Navigation, and Timing
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• v.2 no.1
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• pp.75-80
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• 2013

This article presents the design of long range navigation (LORAN)-disciplined oscillator (LDO), employing the timing information of the LORAN system, which was developed as a backup system that corrects the vulnerability of the global positioning system (GPS)-based timing information utilization. The LDO designed on the basis of hardware generates a timing source synchronized with reference to the timing information of the LORAN-C receiver. As for the LDO-based timing information measurement, the Kalman filter was applied to estimate the measurement of which variance was minimized so that the stability performance could be improved. The oven-controlled crystal oscillator (OCXO) was employed as the local oscillator of the LDO. The controller was operated by digital proportional-integral-derivative (PID) controlling method. The LDO performance evaluation environment that takes into account the additional secondary factor (ASF) of the LORAN signals allows for the relative ASF observation and data collection using the coordinated universal time (UTC). The collected observation data are used to analyze the effect of ASF on propagation delay. The LDO stability performance was presented by the results of the LDO frequency measurements from which the ASF was excluded.

• Computers and Concrete
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• v.25 no.6
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• pp.551-563
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• 2020

This paper investigates the artificial neural network (ANN) to predict the dimensionless parameters for the maximum contact pressures and contact areas of a contact problem. Firstly, the problem is formulated and solved theoretically by using Theory of Elasticity and Integral Transform Technique. Secondly, the contact problem has been extended based on the ANN. The multilayer perceptron (MLP) with three-layer was used to calculate the contact distances. External load, distance between the two quarter planes, layer heights and material properties were created by giving examples of different values were used at the training and test stages of ANN. Program code was rewritten in C++. Different types of network structures were used in the training process. The accuracy of the trained neural networks for the case was tested using 173 new data which were generated via theoretical solutions so as to determine the best network model. As a result, minimum deviation value (difference between theoretical and C++ ANN results) of was obtained for the network model. Theoretical results were compared with artificial neural network results and well agreements between them were achieved.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.2
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• pp.24-31
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• 2001

An axial-type turbine design technology is developed. In order to design one-stage turbine, the preliminary design method is applied, and then design parameters are chosen after analyzing gas properties within the turbine passage using the streamline curvature method. Stator blade is designed using C4 profile, and rotor blade is designed using shape parameters. Stator is manufactured as an integral type and rotor is manufactured to be disassembled from the disc for changing blade incidence angle. The output power from the rotor is measured with various RPM and input power. Experimental results show that the maximum efficiency of turbine rotor is obtained on the design point, and the output power is proportionally decreased with the negative incidence angle even the test turbine is a reaction turbine. The efficiency of turbine rotor is decreased to 5% by $7.5^{\cire}$ negative incidence angle from the designed value.

• Journal of Korean Society of Rural Planning
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• v.2 no.1
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• pp.57-68
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• 1996

Village Renewal(Dorferneuerung) Policy Program in Germany, directly originated from Rural Beutification Movement between mid 18C and mid 19C, has several characteristics as follows. First, we can find out the planned approach in land use and settlement reorganization of Pillage Renewal Program. There are three ways to designate the planning area of the village rearrangement project in countryside. One is to designate the detailed B-plan district by urban plan for the village over some size defined legally. Another is to have a living space of settlement be contained in land allotment project area. In this case, residential areas of several villages related to agricultural land consolidation should be simultaneously designated as the project area. The last is only for the built environment focused on the living space. Second, the emphasis in German village encouragement program can be made on the integral approach through which sets of policy programs of the land allotment, the living environment improvement, the physical landscape management and the cultural resources conservation are intensively implemented together. Third, the bottom-up and community participation approach can be greatly stressed on the planning and implementation process, Community participation, subsidy application to local government by residents themselves, community consensus on architectural style and outdoor spatial form, etc. have been recognized as an effective strategy to accomplish the task of village activity promotion.

• Journal of the Korean Institute of Gas
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• v.1 no.1
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• pp.120-126
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• 1997

The thermal decomposition of low density polyethylene(LDPE) and $25\%{\~}48\%$ chlorinated polyethylene(CPE) were studied using a dynamic thermogravimetry in the stream of nitrogen gas with 20ml/min. The mathematic method, differential (Friedman) and Integral (Ozawa) method were used to obtain value of activation energy of decomposition energy on the reaction. The activation energies evaluated by the above methods agree with each other very well. The maximum average activation energy calculated was 71.71kcal/mol. The thermal decomposition of LDPE and CPE were considered to be carried out by main chain scission and the thermogravimetric trace curve agree with the theoretical equation.

• Wind and Structures
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• v.24 no.2
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• pp.185-204
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• 2017

High-resolution wind measurements at 2.25 m in height were used to investigate the mean and turbulence properties of an extreme thunderstorm wind event in West Texas. These data were combined with single Doppler scans from the Texas Tech University Ka-band mobile Doppler radars systems (TTUKa) to provide meteorological context over the surface measurement stations for portions of the outflow. Several features characteristic of a severe wind event were noted in the radar data, including a bowing portion of the thunderstorm complex and a small circulation on the leading edge. These features were reflected in the surface wind time histories and provided natural separation between various regions of the outflow. These features also contributed to the peak 1-s gust at all measurement stations. The turbulence characteristics of each outflow region were also investigated and compared. Reduced values of running turbulence intensity and elevated values of longitudinal integral scales were noted during the period of peak wind speed. Larger scales of turbulence within the outflow were also suggested via spectral analysis.