• Journal of Biosystems Engineering
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• v.35 no.1
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• pp.21-30
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• 2010

This study was performed to develop an active tire pressure control system that can adjust tire pressure to the optimum level according to traveling and working condition of agricultural tractor. For the development of active tire pressure control system, pneumatic supplier, solenoid valve block including pneumatic supply line, infinite rotation type pneumatic supplier with rotary joint unit, tire pressure transceiver module and control algorithm were developed. Also, tire simulator was developed. Using this tire simulator, the feasibility of each part constructing actual system was tested by checking the performance. The average communication success ratio was 98.3% between tire pressure transmitter and receiver module according to the various tire rotational speed and data receipt position of receiver module. The communication performance of the developed transmitter and receiver module was very stable in any condition. The tire pressure control system was accomplished by using the proportional control algorithm in this study. Also tire pressure control performance of developed control system was analyzed by using the tire simulator. As a result of control performance analysis to the developed system, the developed control system took 307 seconds to inflate agricultural tractor's tire from 50 kPa to 180 kPa. In opposite case, it took 210 seconds. Also it was able to control the tire pressure accurately under ${\pm}0.9%$ (FS) in any condition.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.229-232
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• 2005

In this paper, an image-based "approach-align -grasp" visual servo control design is proposed for the problem of object grasping, which is based on the binocular stand-alone system. The basic idea consists of considering a vision system as a specific sensor dedicated a task and included in a control servo loop, and we perform automatic grasping follows the classical approach of splitting the task into preparation and execution stages. During the execution stage, once the image-based control modeling is established, the control task can be performed automatically. The proposed visual servoing control scheme ensures the convergence of the image-features to desired trajectories by using the Jacobian matrix, which is proved by the Lyapunov stability theory. And we also stress the importance of projective invariant object/gripper alignment. The alignment between two solids in 3-D projective space can be represented with view-invariant, more precisely; it can be easily mapped into an image set-point without any knowledge about the camera parameters. The main feature of this method is that the accuracy associated with the task to be performed is not affected by discrepancies between the Euclidean setups at preparation and at task execution stages. Then according to the projective alignment, the set point can be computed. The robot gripper will move to the desired position with the image-based control law. In this paper we adopt a constant Jacobian online. Such method describe herein integrate vision system, robotics and automatic control to achieve its goal, it overcomes disadvantages of discrepancies between the different Euclidean setups and proposes control law in binocular-stand vision case. The experimental simulation shows that such image-based approach is effective in performing the precise alignment between the robot end-effector and the object.

• Journal of Korea Multimedia Society
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• v.12 no.4
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• pp.502-511
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• 2009

In order to simulate a depth-of-field effect in real world, there have been several researches in computer graphics field. It can represent an out-of-focused scene by calculating focal plane. When a point in a 3D coordinate lies on further or nearer than focal plane, the point is presented as a blurred circle on image plane according to the characteristic of the aperture and the lens. We can generate a realistic image by simulating the effect because it provides an out-of-focused scene like human eye dose. In this paper, we propose a method to calculate a disparity value of a viewer using a customized stereoscopic eye-tracking system and a GPU-based depth-of-field control method. They enable us to generate more realistic images reducing side effects such as dizziness. Since stereoscopic imaging system compels the users to fix their focal position, they usually feel discomfort during watching the stereoscopic images. The proposed method can reduce the side effect of stereoscopic display system and generate more immersive images.

• Composites Research
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• v.12 no.3
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• pp.55-65
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• 1999

In this paper, the thermal buckling and postbuckling behaviour of composite beam with embedded shape memory alloy (SMA) wires are investigated experimentally and analytically. The results of thermal buckling tests on uniformly heated, clamped, composite beam embedded with SMA wire actuators are presented and discussed in consideration of geometric imperfections, slenderness ratio of beam and embedding position of SMA wire actuators. The shape recovery force can reduce the thermal expansion of composite laminated beam, which result in increment of the critical buckling temperature and reduction of the lateral deflection of postbuckling behaviours. It is presented quantitatively on the temperature-load-deflection behaviour records how the shape recovery force affects the thermal buckling. The cross tangential method is suggested to calculate the critical buckling temperature on the temperature-deflection plot. Based on the experimental analysis, the new formula is also proposed to describe the critical buckling temperature of a laminated composite beam with embedded SMA wire actuators.

• Journal of Korean Society of Steel Construction
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• v.20 no.3
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• pp.365-375
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• 2008

The main objective of this paper is to study the behaviour of yLRC composite columns at elevated temperatures by experimental test. The effects of load ratios, cross-section size and fire protection for the yLRC columns were investigate d by the test and compared using the heat transfer analysis perfo rmed based on the finite element program ANSYS 10.0 using the ISO834 standard fire curve, following the main guidelines proposed by the EC4 Part 1.2. As heat transfer is the movement of heat by conduction, convection, and radiation, and as temperature inside an object varies by position and time, time. As the steel's thermal conductivity is higher than that of concrete, steel loses its strength rapidly in a high-temperature situation such as a fire. Fire resistance performance of the yLRC composite column under fire conditions was evaluated througheat transfer analysis for parametric study.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.12
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• pp.1703-1709
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• 2008

As genetic markers, single nucleotide polymorphisms (SNP) are very appropriate for the development of genetic tests for economic traits in livestock. Several microsatellite markers have been identified as useful markers for the genetic improvement of Hanwoo. Among those markers, ILSTS035 was recently mapped at a similar position with four SNPs (AH1_11, AH1_9, 31465_446, and 12273_165) in a linkage map of EST-based SNP in BAT6. Among the four SNPs, two SNPs (31465_446 and 12273_165) were analyzed using BLAST at the NCBI web site. The sequences including the 12273_165 SNP were identified at the intron region within the LOC534614 gene on the gene sequence map (Bos taurus NCBI Map view, build 3.1). The LOC534614 gene represents a protein similar to myosin heavy chain, fat skeletal muscle, embryonic isoform 1 in the dog, and myosin_1 (Myosin heavy chain D) in Macaca mulatta. In cattle, the myosin heavy chain was associated with muscle development. The phenotypic data for growth and carcass traits in the 415 animals were analyzed by the mixed ANCOVA (analysis of covariance) linear model using PROC GLM module in SAS v9.1. By the genotyping of Hanwoo individuals (n = 415) to evaluate the association of SNP with growth and carcass traits, it was shown that the 12273_165 SNP region within LOC534614 may be a candidate marker for growth. The results of the statistical analyses suggested that the genotype of the 12273_165 SNP significantly affected birth weight, weight of the cattle at 24 months of age, average daily gain and carcass cold weight (p<0.05). Consequently, the 12273_165 SNP polymorphisms at the LOC534614 gene may be associated with growth in Hanwoo, and functional validation of polymorphisms in LOC534614 should be performed in the future.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.9-19
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• 2013

In this paper, we develop a Spatio-Temporal graph as of a key component of our knowledge representation Scheme. We design an integrated representation scheme to depict not only present and past but future in parallel with the spaces in an effective and intuitive manner. An event in general occupies not only a space but a time. Hence a crucial premise for the simulation of virtual situations is to position events in the multi-dimensional context, that is, 3-D space extended by the temporal dimension. Furthermore an event tends to have physical, social and mental aspects intertwined. As a result we need diverse information structures and functions to model entities and relations associated with events and to describe situations in different stances or perspectives of the virtual agents. These structures and functions are implemented in terms of integrated and intuitive representation schemes at different levels such as Ontology View, Instance View, ST View, Reality View. The resulting multi-dimensional comprehensive knowledge structure accommodates multi-layered virtual world developing in the time to maximize the diversity of situations in the historical context. The viability of this knowledge representation scheme is demonstrated with a typical scenario applied to a simulator implemented based on the ST Graph. The virtual stage based on the ST graph can be used to provide natural contexts for situated learning or next-generation simulation games.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.76-83
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• 2009

This paper presents a compression method for animated meshes or mesh sequences which have a shared connectivity and geometry streams. Our approach is based on static semi-regular mesh compression algorithm introduced by Khodakovky et al. Our encoding algorithm consists of two stages. First, the proposed technique creates a semi-regular mesh sequence from an input irregular mesh sequence. For semi-regular remeshing of irregular mesh sequences, this paper adapts the MAPS algorithm. However, MAPS cannot directly be performed to the input irregular mesh sequence. Thus, the proposed remesh algorithm revises the MAPS remesher using the clustering information, which classify coherent parts during the animation. The second stage uses wavelet transformation and clustering information to compress geometries of mesh sequences efficiently. The proposed compression algorithm predicts the vertex trajectories using the clustering information and the cluster transformation during the animation and compress the difference other frames from the reference frame in order to reduce the range of 3D position values.

• Ocean and Polar Research
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• v.36 no.4
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• pp.447-454
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• 2014

In August, 2013, we collected epifaunal megabenthos using a deep sea camera (DSC) around a benthic impact study (BIS) site. This was located in the KR5 block of the Korea Deep Ocean Study (KODOS) area in the Northeastern Pacific. The DSC was positioned at $6.8{\pm}2.9m$ (SD) from the sea bottom and was operated from a position at $131^{\circ}56.85^{\prime}-131^{\circ}55.02^{\prime}W$ for 2.3 h at a speed of 1-2 knot. The geographical features of the study area consisted of two structures; a trough in the middle and hills at the east and west sides. Sediment conditions were consistent within six blocks and were affected by slope and polymetallic nodule deposits. We analyzed 226 megafaunal species. Sipunculida comprised the highest percentage of individuals (39%), and the dominant epifaunal megabenthos were Hormathiidae sp., Primnoidae sp., Hexactinellida sp., Hyphalaster inermis, Freyella benthophila, Paelopatides confundens, Psychropotes longicauda, and Peniagone leander. More than 80% of the total density of megafauna occurred on sea plain (D- and E-blocks). We found two distinct groups in the community, one located on sea plains and the other along both sides of the sea slop. Our results suggest that geographical features such as slope and polymetalic nodule deposits are important in controlling the distribution of the epifaunal megabenthos around the KODOS area.

• Journal of Astronomy and Space Sciences
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• v.31 no.2
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• pp.177-186
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• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA) detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL) mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.