• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.83-89
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• 2021

To improve the performance of self-driving cars, the introduction of V2X, a communication technology that connects vehicles, infrastructure, and vehicles, is essential. Even if traffic information of the other vehicle is known, the structure of the intersection and a distance calculation algorithm are required for accurate calculations at roundabouts. This paper proposes a design algorithm for a rotating intersection and implemented in Matlab that complies with the national design rules and enables accurate calculations. Assuming the roundabout and the entrance/exit path to be a circle, a method for measuring the distance between vehicles at an arbitrary point was proposed using the horizontal shift of the entrance circle to the main circle. The algorithm could be used in fully autonomous vehicles by designing a roundabout suitable for the terrain by arbitrarily varying the angle between branches and the radius of curvature of the entrance and exit roads, and transmitting a warning signal when a collision between two driving vehicles is expected.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.422-429
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• 2022

In this paper, the intermediate frequency transmission signal level between the network system-based baseband and RF unit consisting of multi-channel airborne relay devices and a lot of mission devices, which are currently undergoing technology development tasks, is kept constant at the reference signal level. Considering the other party's receiving input range, despite changes in the short-range long-range wireless communication environment, it presents a multi-link protection and MLP-A algorithm that allows signals to be transmitted stably and reliably through signal detection automatic gain control, and experiments and analysis considering short-distance and long-distance wireless environments were performed by designing, manufacturing, and implementing RF units to which MLP-A algorithms were applied, and applying distance calculation equations to the configuration of multiple air movements and verification networks. Through this, it was confirmed that a stable and reliable RF communication system can be operated.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.609-616
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• 2023

In a wireless network environment, since sensors are not always connected to power, the life of a battery, which is an energy source supplied to sensors, is limited. Therefore, various studies have been conducted to extend the network life, and a layer-based routing protocol, LEACH(: Low-energy Adaptive Clustering Hierarchy), has emerged for efficient energy use. However, the LEACH protocol, which transmits fused data directly to the sink node, has a limitation in that it consumes as much energy as the square of the transmission distance when transmitting data. To improve these limitations, this paper proposes an algorithm that can minimize the transmission distance with multi-hop transmission where cluster heads are chained between cluster heads through relative distance calculation from sink nodes in every round.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.1
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• pp.27-38
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• 2004

In this study, the reliability design method developed by Shimosako and Takahashi in 1999 for calculation of the expected sliding distance of the caisson of a vertical breakwater is extended to take into account the variability in wave direction such as directional spreading of waves, obliquity of the deep-water design principal wave direction from the shore-normal direction, and its variation about the design value. To calculate the transformation of random directional waves, the model developed by Kweon et al. in 1997 is used instead of Goda's model, which was developed in 1975 for unidirectional random waves normally incident to a straight coast with parallel depth contours and has been used by Shimosako and Takahashi. The effects of directional spreading and the variation of deep-water principal wave directions were minor compared with those of the obliquity of the deep-water design principal wave direction from the shore-normal direction, which tends to reduce the expected sliding distance as it increases. Especially when we used the field data in a part of east coast of Korea, considering the variability in wave directions reduced the expected sliding distance to about one third of that not considering the directional variability. Reducing the significant wave height calculated at the design site by 6％ to correct the effect of wave refraction neglected in using Goda's model was found to be proper when the deep-water design principal wave direction is about 20 degrees. When it is smaller than 20 degrees, a value smaller than 6％ should be used, or vice versa. When we designed the caisson with the expected sliding distance to be 30㎝, in the area of water depth of 25 m or smaller, we could reduce the caisson width by about 30％ at the maximum compared with the deterministic design, even if we did not consider the variability in wave directions. When we used the field data in a part of east coast of Korea, considering the variability in wave directions reduced the necessary caisson width by about 10% at the maximum compared with that not considering the directional variability, and is needed a caisson width smaller than that of the deterministic design in the whole range of water depth considered (10∼30 m).

• Transactions on Electrical and Electronic Materials
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• v.2 no.1
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• pp.7-11
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• 2001

We measured the electron transport coefficients, the electron drift velocity, W, and the longitudinal diffusion coefficient, $D_{L}$, over the E/N range from 0.03 to 100 Td and gas pressure range from 0.133 to 122 kPa in the 0.526% and 5.05% $C_{3}F_{8}$-Ar mixtures by the double shutter drift tube with variable drift distance. And we calculated these electron transport coefficients by using multi-term approximation of Boltzmann equation analysis. We determined the electron collision cross sections set for $C_{3}F_{8}$ molecule by the comparison of measurement and calculation. Our special attention in the present study was focused upon the inelastic collision cross sections of the $C_{3}F_{8}$ molecule.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1771-1778
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• 2013

For the excited states of a hydrogen molecule up to n = 3 active spaces, potential energy curves (PECs) are obtained for values of the internuclear distance R in the interval [0.5, 10] a.u. within an accuracy of $1{\times}10^{-4}$ a.u. (Hartree) compared to the accurate PECs of Kolos, Wolniewicz, and their collaborators by using the multi-reference configuration-interaction method and Kaufmann's Rydberg basis functions. It is found that the accuracy of the PECs can be further improved beyond $1{\times}10^{-4}$ a.u. for that R interval by including the Rydberg basis functions with angular momentum quantum numbers higher than l = 4.

• Journal of the Korean Chemical Society
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• v.60 no.6
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• pp.410-414
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• 2016

The anharmonic frequency of a local OH stretching mode of a water monomer and dimer was calculated using various levels of density functional theory. The quantum chemical potential energy curves as a function of the OH bond distance were calculated, and they were fitted with the Morse potential function to analytically obtain the fundamental transition frequency. By comparing those values with the frequencies similarly calculated using an ab initio quantum chemical method, the coupled cluster theory including both single and double excitations with the perturbative inclusion of triple excitation in the complete basis limit, the accuracy of various density functional methods in the calculation of anharmonic vibration frequency of water molecules was assessed. For a water monomer, X3LYP and B3LYP methods give the best accuracy, whereas for a water dimer, B972, LCBLYP, ${\omega}B97X$, ${\omega}B97$ methods show the best performance.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.470-473
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• 2002

A communication-aid circuit to detect eye-gazed patterns is proposed in this paper. The circuit is an analog-digital mixed system. By determining the direction of eye-gazed pattern, the circuit detects an eye-gazed pattern from 2-dimensional arrayed patterns on a syllabary. Different from conventional systems, the syllabary is moved to overlap the eye-gazed pattern with the center coordinate of screen. Thus, the proposed circuit can avoid a complex calculation of the distance between the eye-gazed point and the center coordinate. Furthermore: an economical size of hardware can be provided since no full-adders are required by employing floating-gate MOSFBT's. The validity of the cricuit design is confirmed by computer simulations. Furthermore, to implement onto an IC chip, the layout design is performed by using a CAD tool, MAGIC.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1046-1050
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• 2004

Six physical properties (enthalpy, density, decomposition temperature, solubility in water, pKa values, and hydronium potential) were examined by molecular modeling techniques. The molecular connectivity index, Wiener distance index, and Ad hoc descriptor are employed as structural parameters to encode information about branching, size, cyclization, unsaturation, heteroatom content, and polarizability. This paper examines the correlation of the molecular modeling techniques parameters and the physicochemical properties of amino acids. As a results, calculated values were in agreement with experimental data in the above six physical properties of amino acids and the molecular connectivity index was superior to the other indices in fitting the calculated data.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.3
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• pp.148-154
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• 2005

Various methods for analyze optical components which are necessary before the fabrication of optical circuit component and as its applications, designing method of Wavelength Division Multiplexer(WDM) filter using arrayed-waveguide grating(AWG) is paper. In the case of analyzing uniform optical waveguide, effective index method(EIM), harmonic expansion method are used, and in the case of non-uniform optical waveguide, beam propagation method(BPM) are used. In this paper, to use arrayed-waveguide grating as WDM filter of centered wavelength of $1.55{\mu}m$ and wavelength spacing of 0.8nm, all of the parameter of AWG is calculated by the HEM and the BPM using EIM. As a result of calculation, free spectral range is 12.8nm, focal length $9336.55{\mu}m$, path difference $129.36{\mu}m$ and the number of slab waveguide 91 when the distance of core center to center on row land circle is $20{\mu}m$.