• Journal of Institute of Control, Robotics and Systems
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• v.11 no.3
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• pp.214-221
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• 2005

For decades, airships have being developed in Europe (especially German) and America. Airships are planning to be used for advertisements and airliners as well. In Korea, KARI (Korea Aerospace Research Institute) is developing stratospheric communication airship and the similar research is carried out in Japan. Among them, Zeppelin of German has the cutting-edge airship technology with Zeppelin NT. In this paper, the flight performance and stability were evaluated by comparing mathematical theory and the real test. The stability was examined through dynamic modeling and assured by designing controllers at each flight mode. Elevator angle, rudder angle, magnitude of thrust and tilting angle of thrust vector were used as control inputs. Moreover, after measuring the airship velocity, flight direction, magnitude and direction of the wind, attitude angles and trajectories of the airship at each flight mode, the results were compared with the simulation. To get the reasonable data, low-pass filter and band-stop filter were designed to get rid of the sensor noise and engine vibration. The test was accomplished at cruise mode, turning mode, and deceleration. To conclude, with comparing the simulation data and flight test data, it could be known that the dynamic model used in this paper was reasonable.

• The Research Journal of the Costume Culture
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• v.11 no.4
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• pp.562-577
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• 2003

The object of my research is to inquiry into the immediate constituent and techniques of underwear after looking into basic theory of underwear, techniques by materials classified according to the matter of elasticity, and studying flat pattern and draping which are basis of corset and brassiere structure focusing on corsetry among underwears and production techniques. Various papers are referenced for theoretical study and the elements and techniques of underwear are analyzed based on photographical materials. This paper concludes as follows. To make the flat pattern of corset and brassiere fit to the body tightly, design dart two times without any space and draw smaller than the body. To support the breast sufficiently, move the side seam 1¼″ to the front panel and the seam should pass the apex in all occasions. For draping, dart should be added into short of elasticity materials in the past but dart is no use these days since the material today is extremely elastic. It is possible now to show the body line with only the seam or a pattern. In a case of elastic material, set the elastic direction to the grain line and have a draping as pulling from the center to the out side. As production technic, for an hem, put a zigzag stitch in elastic materials with a 10-20% short elastic band, pulling the band. Then make 3/16″-1/4″ short inseam.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.12
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• pp.691-698
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• 2003

In this paper, we propose a problem, called one-to-one disjoint path cover problem, whether or not there exist k disjoint paths joining a pair of vertices which pass through all the vertices other than the two exactly once. A graph which for an arbitrary k, has a one-to-one disjoint path cover between an arbitrary pair of vertices has a hamiltonian property stronger than hamiltonian-connectedness. We investigate this problem on recursive circulants and prove that for an arbitrary k $k(1{\leq}k{\leq}m)$$ G(2^m,4)$,$m{\geq}3$, has a one-to-one disjoint path cover consisting of k paths between an arbitrary pair of vortices.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.381-383
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• 2005

This paper is concerned with the prediction of micro structural changes of Al alloys during cryogenic rolling using an Eulerian finite element analysis. The main objective of cryogenic rolling is to obtain ultra-fine grains by severe plastic deformation at the extremely low temperature. Thereby, this simulation focuses on micro structural developments - the texture development and the changes in the size and shape of grains. The former one may be modeled using a crystal plasticity theory while the other can be predicted by a streamline technique. Applications to three pass rolling are given.

• Journal of the Korean Applied Science and Technology
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• v.16 no.1
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• pp.75-81
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• 1999

HF purification performance of an ion exchange membrane(IEM) was evaluated with 0.5% HF spiked with 10ppb of Fe, Ni and Cu nitrates. The result show that after less than five turnovers through an IEM, the metallic impurity concentration drops below 1ppb. The decrease rate can be fitted to a model assuming the experimental tanks to be continuously stirred tank reaction and that the metallic impurity concentration after the IEM is a function of the single-pass purification efficiency of the membrane, the concentration before purification and the metals desorbed form the IEM. The Concentration after purification was investigated up to a cumulative Fe loading of 300ppb in the 23 liter recirculated loop. It increases linearly vs. cumulative loading and can be explained by the Langmuir theory resulting in a purification efficiency at the equilibrium of close to 99.5% in this loading regime.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1480-1482
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• 2005

The major causes of power quality deterioration are harmonic current through semiconductor switching device, due to use of nonlinear loads such as diodes rectifier or thyristor rectifiers. In response to this concerns, this paper presents a new control method of single-phase active power filter(APF) for the compensation of harmonic current components in nonlinear loads. In order to make the complex calculation to be possible, the single-phase system that has two phases was made by constructing a imaginary second-phase giving time delay to load currents. In the conventional method, a imaginary-phase lagged to the load current T/4(here T is the fundamental cycle) was made. But in this proposed method, the new signal, which has the delayed phase through the filter, using the phase-delay property of low-pass filter, was used as the second phase. As this control method is applied to the system of single phase, an instantaneous calculation was done rather by using the rotating reference frames that synchronizes with source-frequency than by applying instantaneous reactive power theory that uses the conventional fixed reference frames.

• Journal of Korea Trade
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• v.23 no.3
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• pp.52-67
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• 2019

Purpose - This study analyzes the effect of the authorized economic operator-mutual recognition arrangement (AEO-MRA) on the performance of Korean exporters and importers. The effect of the import-export companies' characteristics, such as annual sales, the number of foreign markets, and overseas experience, on the AEO-MRA is deduced; the relationship between this effect and firm performance is analyzed. Design/methodology - An empirical research model was constructed and analyzed using structural equation modeling. The effect of AEO-MRA on logistics and operational performance was derived from the aforementioned characteristics as leading factors of the AEO-MRA. The regulatory influence of cooperation with logistics companies was analyzed in the AEO-MRA effect on logistics performance. Thus, 172 valid samples were obtained from import-export companies certified by the AEO-MRA. Findings - Among the aforementioned characteristics, only "annual sales" has a positive effect on the AEO-MRA, whose effect enhances logistics and operational performances. The AEO-MRA effect did not directly affect operational performance. Owing to the adjustment effect analysis, the AEO-MRA effect and logistics performance relationship is strengthened if the cooperative relationship with the logistics company is higher than a certain level. If this cooperation falls below a certain level, the AEO-MRA effect on logistics performance reduces. Thus, logistics cooperation is an important factor in the AEO-MRA effect and logistics performance relationship. Originality/value - Hinging on the resource-based theory and relational viewpoint, an empirical model that explains the relationship between the AEO-MRA effect and firm performance is established.

• Journal of ILASS-Korea
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• v.26 no.4
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• pp.212-218
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• 2021

The present study aims to develop the Surface Plasmon Resonance (SPR) imaging system facilitating the real-time measurement of the concentration of evaporating binary mixture droplet (BMD). We introduce the theoretical background of the SPR imaging technique and its methodology for concentration measurement. The SPR imaging system established in the present study consists of a LED light source, a polarizer, a lens, and a band pass filter for the collimated light of a 589 nm wavelength, and a CCD camera. Based on the Fresnel multiple-layer reflection theory, SPR imaging can capture the change of refractive index of evaporating BMD. For example, the present study exhibits the visualization process of ethylene glycol (EG)-water (W) BMD and measures real-time concentration change. Since the water component is more volatile than the ethylene glycol component, the refractive index of EG-W BMD varies with its mixture composition during BMD evaporation. We successfully measured the ethylene glycol concentration within the evaporating BMD by using SPR imaging.

• Steel and Composite Structures
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• v.52 no.5
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• pp.571-581
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• 2024

After a disaster like the catastrophic earthquake, the government have to use rapid assessment of the condition (or damage) of bridges, buildings and other infrastructures is mandatory for rapid feedbacks, rescue and post-event management. This work studies the tracking control problem of a class of strict-feedback nonlinear systems with input saturation nonlinearity. Under the framework of dynamic surface control design, RBF neural networks are introduced to approximate the unknown nonlinear dynamics. In order to address the impact of input saturation nonlinearity in the system, an auxiliary control system is constructed, and by introducing a class of first-order low-pass filters, the problems of large computation and computational explosion caused by repeated differentiation are effectively solved. In response to unknown parameters, corresponding adaptive updating control laws are designed. The goals of this paper are towards access to adequate, safe and affordable housing and basic services, promotion of inclusive and sustainable urbanization and participation, implementation of sustainable and disaster-resilient buildings, sustainable human settlement planning and manage. Simulation results of linear and nonlinear structures show that the proposed method is able to identify structural parameters and their changes due to damage and unknown excitations. Therefore, the goal is believed to achieved in the near future by the ongoing development of AI and control theory.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.471-477
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• 2019

The purpose of this study is to analyse the attacking pattern of the key player through plenty of passes on field hockey between the winning games and losing ones through the preliminary game and the tournament. It has shown that the Korean women national team on field hockey is analysed all the passes through the sportscode for the 6 games of the World-League Final, and is investigated the centrality through the social network analysis using the R analytic software. The result is followed : First, It has shown three tendencies on the preliminary games that it has shown a lower Degree-Centrality, a same with Closeness, and a higher Betweenness than the tournament. Second, It has also described on winning games that it has explained a lower Degree-Centrality, a same with Closeness, and a higher Betweenness than losing games. On the conclusion, it has revealed that Korean women national team on field hockey showed a tendency that prefer to use a counter-attacking. Based on these study, expect to be used as a way to analyze performance in the field.