• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.146-153
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• 1998

NC machines with 4 or 5 axes are capable of various tool approach motions, which makes interference-free and high machinablity machining possible. This paper deals with how to integrate these two advantages (interference-free and high machinability machining) in multi-axes NC machining with a ball-end mill. Feasible tool approach region at a point on a surface is first computed, then among which an approach direction is determined so as to minimize the cutting force required. Tool and spindle volumes are considered in computing the feasible tool approach region, and the computing time is improved by trans-forming surface patches into minimal enclosing spheres. A cutting force prediction model is used for estimating the cutting force. The algorithm is developed so as to be applied to 4- or 5-axes NC machining in common.

• Molecules and Cells
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• v.24 no.1
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• pp.27-36
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• 2007

The hypothetical protein TTC0263 of Thermus thermophilus HB27 is a thermophilic tetratricopeptide repeat (TPR)-containing protein. In the present study, the TPR region (residues 26-230) was resolved at $2.5{\AA}$ with R-factors of $R/R_{free}$ = 23.6%/28.6% $R/R_{free}=23.6%/28.6%$. TTC0263 consists of 11 helices that form five TPR units. Uniquely, it contains one atypical "extended" TPR (eTPR) unit. This comprises extended helical residues near the loop region of TTC0263, such that the helical length of eTPR is longer than that of the canonical TPR sequence. In addition, the hybrid TPR domain of TTC0263 possesses oligomer-forming characteristics. TPR domains are generally involved in forming multi-subunit complexes by interacting with each other or with other subunit proteins. The dynamic structure of TTC0263 described here goes some way to explaining how TPR domains mediate the formation of multi-subunit complexes.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1011-1014
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• 1999

In this paper, a new algorithm has been presented that helps to preserve diversity as well as to enhance the convergence speed of the evolutionary programming. This algorithm is based on the cell partitioning of search region for preserving the diversity. Until now, the greater part of researches is not concerned about preserving the diversity of individuals in a population but improving convergence speed. Although these evolutions are started from multi-point search at the early phase, but at the end those search points are swarming about a one-point, the strong candidate. These evolutions vary from the original idea in some points such as multi-point search. In most case we want to find the only one point of the best solution not several points in the vicinity of that. That is why the cell partitioning of search region has been used. By restricting the search area of each individual, the diversity of individual in solution space is preserved and the convergence speed is enhanced. The efficiency of the proposed algorithm has been verified through benchmark test functions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.2
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• pp.649-658
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• 1996

Small-amplitude harmonic oscillations of multi-cylinders are considered both experimentally and theoretically. For the theoretical model, the flow regime is separated into inner and outer regions. In the inner region, the flow is governed by the generalized Stokes boundary layer equation. In the outer region, the full Navier-Stokes equation for the steady streaming flow is solved numerically by using ADI scheme and FVM coupled with the boundary integral method. Flow visualization experiments are conducted by using the Laser Sheet Image Technique. The case of two circular cylinders and square cylinders with variable distances are chosen as a typical example. Although experimental results are based on the flow in the finite domain, both experimental and numerical results agree well qualitatively. As the separation of cylinders is increased, a numerical result shows the asymptotic convergence to a single cylinder case.

• Journal of Aerospace System Engineering
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• v.3 no.1
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• pp.1-5
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• 2009

The flight control of the T-50 advanced trainer is conducted by the digital FBW (Flight-by-Wire) control system. The system input data consist of flight conditions such as altitude, airspeed, and angle of attack. And the flight conditions of the aircraft are obtained from IMFP (Integrated Multi-Function Probe). The T-50 aircraft equip three IMFP sensors. To ensure reliability in flight condition data obtained from each IMFP sensor, the mean value of flight conditions is used as the input of the control system. In this study, the effect of an installation angle of IMFP sensors on estimation of flight altitude was investigated by flight test results in the supersonic region.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.2
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• pp.167-175
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• 1999

B.P.F.(Blade Passing Frequency) levels were measured with the cut-off clearance changes. The velocity inside the scroll, pressure fluctuation at cut-off region, and the scroll surface pressure distribution along the scroll from the cut-off to outlet were measured. With a certain cut-off clearance the improvement of efficiency and attenuation of B.P.F. noise level could be achieved. The measured results of pressure fluctuation and scroll surface pressure distribution showed that the secondary flow inside the scroll increased B.P.F. noise level at the cut-off region as the cut-off clearance got wide.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.2
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• pp.71-77
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• 2000

A multi-region model for solute transport through saturated soils has been developed to describe preferential flow. The model consists of numerous discrete pore groups, which are characterized by a discrete dispersion coefficient, flow velocity, and porosity . The hydraulic properties for each pore group are derived from a soil's hydraluic conductivity and soil water characteristic functions . Flow in pore group is described by the classical advection-disersion equation (ADE). An implict finite difference scheme was applied to the governing equation that results in a block-tridiagonal system of equations that is very efficient and allows the soil to be divided into any number of pore groups. The numerical technique is derived from methods used to solve coupled equations in fluid dynamics problems and can also be applied to the transport of interacting solutes. The results of the model are compared to the experimental data from published papers. This paper contributes on the characteristics of the method when applied to the parallel porosity model to describe preferential flow of solutes in soil.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3333-3350
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• 2019

The smart jammer launches jamming attacks which degrade the transmission reliability. In this paper, smart jamming attacks based on the communication probability over different channels is considered, and an anti-jamming Q learning algorithm (AQLA) is developed to obtain anti-jamming knowledge for the local region. To accelerate the learning process across multiple regions, a multi-regional intelligent anti-jamming learning algorithm (MIALA) which utilizes transferred knowledge from neighboring regions is proposed. The MIALA algorithm is evaluated through simulations, and the results show that the it is capable of learning the jamming rules and effectively speed up the learning rate of the whole communication region when the jamming rules are similar in the neighboring regions.

• Journal of Korea Multimedia Society
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• v.17 no.9
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• pp.1070-1075
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• 2014

Due to a number of illegal copied videos, many video content markets have been threatened. Since this copied videos have intercepted the profits of the content holders, content developers lose the will to generate new contents. Therefore, video copy detection approaches have been developed to protect the copyrights of video contents. However, many illegal uploader who generate copied videos used video transformations to avoid video copy detection systems. Among of the video transformations, rotation and flipping did not distorted the quality of video contents. Thus, these two video transformations were adopt to generate copied video. In order to detect rotated or flipping copy videos, rotation and flipping robust region binary pattern (RFR) recently was proposed. But, this RFR has a weakness according to rotated angles. Therefore, in order to overcome this problem, multi region binary patterns are proposed in this paper. The proposed method has the similar performance with the original RFR. But, it showed much higher efficiency for memory spaces.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.90.1-90.1
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• 2013

To better understand the physics underlying the eruption of prominences in solar active regions, we studied eruption processes of two active prominences located in the active region NOAA 11261 using multi-wavelength observational data with high temporal and spatial resolution. Specifically, we examined (1) the temporal variation of morphology and plasma properties of the two active prominences, (2) magnetic fields and their evolution on the photospheric surface underneath the prominences, and (3) the time profiles and locations of radio, EUV, and soft/hard X-ray emissions produced by the M9.3 flare related to the prominence eruption. As a result, we found that: (1) a prominence F1 began to erupt and expand as the abrupt and intense EUV brightening occurred in the localized region underneath the western part of F1 at 03:45 UT prior to the peak time of the M9.3 flare, (2) F1 split into two parts: i.e., the western part asymmetrically erupted by producing the M9.3 flare with microwave source motions along the magnetic polarity inversion line between the two flare ribbons, while the eastern part coalesced into a pre-existing prominence F2, (3) F2 became unstable due to the coalescence with the eastern part of F1, and then it partially erupted with clockwise untwisting motions.