• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.5
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• pp.277-282
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• 2015

During hot and humid weather, air-conditioners consume a large amount of electricity due to the large amount of latent heat. Simultaneous usage of a dehumidifier may reduce latent heat and reduce electricity consumption. In this study, dehumidification performance was measured for a small-sized dehumidification rotor made of inorganic fiber impregnated with metallic silicate within a constant temperature and humidity chamber. Regeneration to dehumidification depends on ratio, rotor speed, room temperature, regeneration temperature, room relative humidity and frontal velocity to the rotor. Results demonstrate an optimum area ratio (1/2), rotor speed (1.0 rpm), and regeneration temperature ($100^{\circ}C$) to achieve a dehumidification rate of 0.0581 kg/s. As the area ratio increases, the optimum rotation speed and the optimum regeneration temperature also increase. Above the optimum rotor speed, incomplete regeneration reduces dehumidification. Above the optimum regeneration temperature, increased temperature variation between regeneration and dehumidification reduces dehumidification. Dehumidification rate also increases with an increase of relative humidity, dehumidification temperature and flow velocity into the rotor.

• The Journal of Korea Robotics Society
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• v.3 no.2
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• pp.91-98
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• 2008

This paper describes the recognition method of moving objects in mobile robot with an omnidirectional camera. The moving object is detected using the specific pattern of an optical flow in omnidirectional image. This paper consists of two parts. In the first part, the pattern of an optical flow is investigated in omnidirectional image. The optical flow in omnidirectional image is influenced on the geometry characteristic of an omnidirectional camera. The pattern of an optical flow is theoretically and experimentally investigated. In the second part, the detection of moving objects is presented from the estimated optical flow. The moving object is extracted through the relative evaluation of optical flows which is derived from the pattern of optical flow. In particular, Focus-Of-Expansion (FOE) and Focus-Of-Contraction (FOC) vectors are defined from the estimated optical flow. They are used as reference vectors for the relative evaluation of optical flows. The proposed algorithm is performed in four motions of a mobile robot such as straight forward, left turn, right turn and rotation. Experimental results using real movie show the effectiveness of the proposed method.

• Journal of Power System Engineering
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• v.17 no.5
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• pp.121-127
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• 2013

In this paper, we propose a distance measurement system for automatic berthing control using a stereo camera mounted on a rotation control device, and a radial pattern target. Automatically controlling the position and attitude of a ship aims to prevent maritime accidents due to human error. Our goal is to measure the relative distance between a ship and an onshore or offshore target for berthing. Therefore, the distance should be continuously measured while tracking a fixed point on a target. To this end, we developed a stereo camerabased distance measurement system that satisfied these requirements. This paper describes the structure and principle of the measurement system. We validate the distance error for target incline due to the relative position and attitude between a camera and a target in miniature scale. In addition, the findings of an experiment in an outdoor environment demonstrate that the proposed measurement system has accuracy within 1 m at a range of 20-100 m which is the acceptable accuracy for automatic berthing.

• Journal of Korea Foundry Society
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• v.24 no.5
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• pp.273-280
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• 2004

Vibrational motions of the compaction table were investigated to select the optimal operation conditions of sand filling and compaction for the EPC process. Their modes were measured at the nine points of the table with changing the relative rotation angles between the two eccentric mass vibrators which were attached parallel beneath the table. Well-defined vibration modes were measured at the center of the table but those of left and right sides of the table were distorted regardless of rotational angle differences. The distortion of vibration modes at both sides of the table were caused by the moment generated by offset positions of two eccentric masses. It was found that the uniform vibration modes would be gathered by controlling the relative distances between the rotating axis and the center of gravity in the compaction system at the various conditions of vibration modes and rotational angle differences.

• Earthquakes and Structures
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• v.14 no.6
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• pp.525-535
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• 2018

This study presents a new beam-column model comprising material nonlinearity and joint flexibility to predict the nonlinear response of reinforced concrete structures. The nonlinear behavior of connections has an outstanding role on the nonlinear response of reinforced concrete structures. In presented research, the joint flexibility is considered applying a rotational spring at each end of the member. To derive the moment-rotation behavior of beam-column connections, the relative rotations produced by the relative slip of flexural reinforcement in the joint and the flexural cracking of the beam end are taken into consideration. Furthermore, the considered spread plasticity model, unlike the previous models that have been developed based on the linear moment distribution subjected to lateral loads includes both lateral and gravity load effects, simultaneously. To confirm the accuracy of the proposed methodology, a simply-supported test beam and three reinforced concrete frames are considered. Pushover and nonlinear dynamic analysis of three numerical examples are performed. In these examples the nonlinear behavior of connections and the material nonlinearity using the proposed methodology and also linear flexibility model with different number of elements for each member and fiber based distributed plasticity model with different number of integration points are simulated. Comparing the results of the proposed methodology with those of the aforementioned models describes that suggested model that only uses one element for each member can appropriately estimate the nonlinear behavior of reinforced concrete structures.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.394-400
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• 2012

SURF is a robust local invariant feature descriptor and has been used in many applications such as object recognition. Even though this algorithm has similar matching accuracy compared to the SIFT, which is another popular feature extraction algorithm, it has advantage in matching time. However, these descriptors do not consider relative location information of extracted interesting points to guarantee rotation invariance. Also, since they use gray image of original color image, they do not use the color information of images, either. In this paper, we propose a method for improving matching performance of SURF descriptor using the color and relative location information of interest points. The location information is built from the angles between the line connecting the centers of interest points and the orientation line constructed for the center of each interest points. For the color information, color histogram is constructed for the region of each interest point. We show the performance of our scheme through experiments.

• The korean journal of orthodontics
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• v.45 no.5
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• pp.236-244
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• 2015

Objective: The aim of this study was to investigate three-dimensional molar displacement after distalization via miniscrews and a horizontal modification of the trans-palatal-arch (TPA). Methods: The subjects in this clinical trial were 26 Class II patients. After the preparation of a complete set of diagnostic records, miniscrews were inserted between the maxillary 2nd premolar and 1st molar on the palatal side. Elastic modules connected to the TPA exerting an average force of 150-200 g/side parallel to the occlusal plane were applied. Cone-beam computed tomography was utilized to evaluate the position of the miniscrews relative to the adjacent teeth and maxillary sinus, and the direction of force relative to molar furcation. The distances from the central point of the incisive papilla to the mesiopalatal cusps of the 1st maxillary molars and the distances between the mesiopalatal cusps of the left and right molars were measured to evaluate displacement of the maxillary molars on the horizontal plane. Interocclusal space was used to evaluate vertical changes. Results: Mean maxillary 1st molar distalization was $2.3{\pm}1.1mm$, at a rate of $0.4{\pm}0.2mm/month$, and rotation was not significant. Intermolar width increased by $2.9{\pm}1.8mm$. Molars were intruded relative to the neighboring teeth, from 0.1 to 0.8 mm. Conclusions: Distalization of molars was possible without extrusion, using the appliance investigated. The intrusive component of force reduced the rate of distal movement.

• Bulletin of the Korean Chemical Society
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• v.31 no.3
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• pp.653-663
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• 2010

Enantioselective total synthesis of (-)-clavosolide A and B was reported in full including the synthesis of proposed structure of (-)-clavosoldie A (1), revised structure of (-)-clavosoldie A (5), and revised structure of (-)-clavosoldie B (6). The relative and absolute stereochemistries of the natural products were confirmed unambiguously by comparing the optical rotation values and $^1H$ and $^{13}C$ NMR spectra of them.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.367-367
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• 2012

We investigate Landau level spectra of twisted bilayer graphene under a perpendicular magnetic field, showing that the layers provide rich electronic structure depending on misoriented angle. New types of excitations with Landau level sequences due to the reflection of interlayer coupling level are matter of interest in the present work. We calculate the electronic structure of bilayer systems with a relative small angle rotation of the two graphene layers. Calculated Landau level spectra for twisted bilayer graphene using a continuum formulation are in good agreement with existing experimental and theoretical studies. Twist angle dependent numerical simulations provide significant insights for the nature of the Landau level spectra in bilayer graphene, combining signals from both massive and massless Dirac fermions. We finally discuss the influence of the graphene layers in the experimental sample that related to the magneto-transport measurements including quantum Hall conductance.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.499-505
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• 2001

The objective of the paper was to measure the pressure drop and to investigate the recirculation region of the conical orifices used in Kwang-yang Iron & Steel Company. The flow field with water used as a working fluid was the turbulent flow for Reynolds number of $2{\times}10^4$. The effective parameters for the pressure drop and the recirculation region were the conical orifice's inclined angle (${\theta}$) against the wall, the interval(L) between orifices, the relative angle of rotation(${\alpha}$) of the orifices, the shape of the orifice's hole(circle, rectangle, triangle) having the same area. It was found that the shape of the orifice's hole affected the pressure drop and the flow field a lot, But the other parameters did not make much differences to the pressure drop. The PISO algorithm with FLUENT code was employed.