• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4C
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• pp.433-439
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• 2007

This paper derives an approximate expression for the output SINR(Signal to Interference plus Noise Ratio) of Applebaum type adaptive array under the scenario of the interferer's proximity to the desired signal. The approximation is made in terms of array geometry, the arrival direction of desired signal and that of an interfering signal. An interferer in the close proximity of target signal is shown to drastically impair the away performance. An approximate expression for interferer arrival direction which results in a predetermined performance loss is also obtained in terms of array configurations. Proposed approximation agrees with the computer calculated performance impairment when the two signals are apart by less than eight degrees. The allowable proximity of the interfering signal increases with the number of array elements.

• Journal of the Korean Institute of Gas
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• v.6 no.4 s.18
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• pp.53-58
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• 2002

In this research, the goal is to ascertain the potential danger when transporting hazardous material by considering the important elements that contribute to such situation, instead of relying on the quantitative risk assessment of fixed facilities. Also, this study will verify the social and personal risk according to damage zone limits, by applying the worst case scenario and the alternative scenario that occur during the transportation process. Moreover, it has selected the optimum transportation route for maximum safety. The result of this research could be used to construct a systematic emergency system that can minimize the damage from serious industrial accidents, by effectively decreasing the danger zone and forming a connection between the community, the society, and the industries according to such evaluations.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.1
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• pp.77-86
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• 2002

This paper proposes a modified Duvall beamformer performing spatial smoothing with spatial interpolation. In the proposed beamformer, virtual array signals are generated by spatial interpolation between each neighbor array elements, then all signals are used to perform spatial smoothing. The proposed beamformer overcomes the loss of degrees of freedom caused by spatial smoothing by forming subarrays with interpolated signals. Mathematical description shows that the proposed beamformer can restore the rank of away covariance matrix. Accordingly, the proposed beamformer can minimize the loss of degrees of freedom. Simulation results show that the proposed beamformer can remove all coherent interferences while conventional beamformers cannot.

• Applied Microscopy
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• v.43 no.2
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• pp.75-80
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• 2013

The morphological features of pollen grains collected from the broad-leaved and cylindrical-leaved Portulaca species of the Hawaiian Islands were investigated. The variation in size and surface pattern were examined using scanning electron microscopy and statistical analysis. Pollens of the Portulaca were apolar grains of monads exhibiting apertures, colpi, and relatively thin echini. Of particular interest was the differing size of pollen grains among the species studied. Pollens of the broad-leaved Portulaca were considerable in size with a length of about $73{\sim}86{\mu}m$, while the cylindrical-leaved Portulaca tended to have smaller pollen grains ranging from 50~65 in diameter. The smallest pollens were found in cultivar 2 having an average of $43{\mu}m$. The pollen was intectate, and the exine surface appeared granulous, having sculptured elements of spinules and puncta. Two types of puncta were discerned; one forming an operculum, and the other, a simple perforation. Numerous spinules and small puncta were found throughout the cylindrical-leaved Portulaca. In the present study, morphological features of pollen grains from ten Hawaiian Portulaca species, including endemic and unknown taxa, revealed the aforementioned pattern of variation. This paper aim to provide morphological information that could be of phylogenetic value within the Hawaiian Portulaca.

• Steel and Composite Structures
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• v.22 no.4
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• pp.915-935
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• 2016

Steel systems composed of Reinforced Concrete column to Steel beam connection (RCS) have been raised as a structural system in the past few years. The optimized combination of steel-concrete structural elements has the advantages of both systems. Through beam and through column connections are two main categories in RCS systems. This study includes finite-element analyses of mentioned connection to investigate the seismic performance of RCS connections. The finite element model using ABAQUS software has been verified with experimental results of a through beam type connection tested in Taiwan in 2005. According to verified finite element model a parametric study has been carried out on five RCS frames with different types of lateral restraint system. The main objective of this study is to investigate the forming of plastic hinges, distribution of stresses, ductility and stiffness of these models. The results of current research showed good performance of composite systems including concrete column-steel beam in combination with steel shear wall and bracing system, are very desirable. The results show that the linear stiffness of models with X bracing and steel shear wall increase remarkably and their ultimate strength increase about three times rather than other RCS frames.

• Steel and Composite Structures
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• v.25 no.5
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• pp.625-638
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• 2017

This paper presents a novel approach that describes the first-order (linear elastic) partial interaction analysis of members formed by multi-components based on the Generalised Beam Theory (GBT). The novelty relies on its ability to accurately model the partial interaction between the different components forming the cross-section in both longitudinal and transverse directions as well as to consider the cross-sectional deformability. The GBT deformations modes, that consist of the conventional, extensional and shear modes, are determined from the dynamic analyses of the cross-section represented by a planar frame. The partial interaction is specified at each connection interface between two adjacent elements by means of a shear deformable spring distributed along the length of the member. The ease of use of the model is outlined by an application performed on a multi-component member subjected to an eccentric load. The values calculated with an ABAQUS finite element model are used to validate the proposed method. The results of the numerical applications outline the influence of specifying different rigidities for the interface shear connection and in using different order of polynomials for the shape functions specified in the finite element cross-section analysis.

• BMB Reports
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• v.50 no.10
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• pp.522-527
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• 2017

A large number of transcriptional activation domains (TADs) are intrinsically unstructured, meaning they are devoid of a three-dimensional structure. The fact that these TADs are transcriptionally active without forming a 3-D structure raises the question of what features in these domains enable them to function. One of two TADs in human glucocorticoid receptor (hGR) is located at its N-terminus and is responsible for ~70% of the transcriptional activity of hGR. This 58-residue intrinsically-disordered TAD, named tau1c in an earlier study, was shown to form three helices under trifluoroethanol, which might be important for its activity. We carried out heteronuclear multi-dimensional NMR experiments on hGR tau1c in a more physiological aqueous buffer solution and found that it forms three helices that are ~30% pre-populated. Since pre-populated helices in several TADs were shown to be key elements for transcriptional activity, the three pre-formed helices in hGR tau1c delineated in this study should be critical determinants of the transcriptional activity of hGR. The presence of pre-structured helices in hGR tau1c strongly suggests that the existence of pre-structured motifs in target-unbound TADs is a very broad phenomenon.

• ALGAE
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• v.21 no.4
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• pp.433-443
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• 2006

This study was performed to understand the morphological and ecological characteristics of Peridinium bipes var. occultatum Lindem., which is the organism responsible for freshwater red tides in Sangsa dam and Miryang dam reservoirs. The samples were collected from April to July 2004 when the freshwater red tides occurred. In the study, we were able to differentiate P. bipes var. occultatum from P. bipes, a closely related species, by its smaller antapical horn size. In Miryang dam reservoir the red tide occurred only within the area of the upstream, but it was well developed in all of the water area in Sangsa dam reservoir. In 2004 average LTSI (Lake Trophic Status Index; Yang and Dickman, 1993) of Miryang dam reservoir was 3.53 of mesotrophic state and Sangsa dam reservoir was 8.59 of eutrophic state. It was determined, through culture experiments under various conditions that vitamins, trace elements, phosphorus and nitrogen were important contributing factors to the growth of P. bipes var. occultatum. A rapid toxic effect of P. bipes var. occultatum on aquatic organisms such of Daphnia magna and Oryzias latipes was not identified in this study.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2397-2405
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• 2000

The remeshing is a method to replace a distorted mesh by a new mesh without interrupting the finite element calculation. The remeshing procedure in this paper refers to the rezoning, for which a sm oothing process is developed to alleviate the distortions of mesh. In the paper, an automatic finite element rezoning system with tetrahedral elements for large deformation analysis has been developed. Our smoothing process is composed of two steps, a surface smoothing and a volume smoothing. In the surface smoothing, checking the dihedral angle and projection on surface patch reduced the change of shape and nodes penetrating die. The constrained Laplacian smoothing has been employed for the volume smoothing process. The state variables are mapped from old mesh to new mesh by using volume coordinates within a tetrahedral element. All these procedures have been linked to the NIKE3D program As illustrated in the examples the overall strategy ensures a robust and efficient rezoning scheme for finite element simulation of metal-forming processes.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.6
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• pp.84-91
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• 1999

The goal of this study is to analyse the stress and the strain occurring within the work piece at the fine-blanking process and hence to assume the size direction and a distribution chart of the shearing stress as the penetration of the punch is being increased trough the application of the FEM. For this analysis we introduced the piece-wise linear method in the non linear structural analysis program for large deformation sheet metal forming and we defined it as the problem of the non linear contact. Therefore we modeled the above problems as quadratic-nodded axi-symmetrical elements for the character-istics of the work piece. From the result of this analysis it was found that the shearing stress is a great deal occurred on the surface of the work piece during the beginning process of the punch penetration and it's effect is expected to influence importantly for the formation of burnish because the deeper is the penetration of the punch in the narrow clearance zone. the greater is the degree of the strain stress.