• Steel and Composite Structures
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• v.38 no.5
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• pp.547-562
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• 2021

This paper aims to explore the mechanical behavior and moment-rotation model of blind bolted joints between concrete-filled double skin steel tubular columns and steel-concrete composite beams. For this type of joint, the inner tube and sandwiched concrete were additionally identified as basic components compared with CFST blind bolted joint. A modified moment-rotation model for this type of connection was developed, of which the compatibility condition and mechanical equilibrium were employed to determine the internal forces of basic components and neutral axis. Following this, load transfer mechanism among the inner tube, sandwiched concrete and outer tube was discussed to assert the action area of the components. Subsequently, assembly processes of basic coefficients in terms of their stiffness and resistances based on the component method by simplifying them as assemblages of springs in series or in parallel. Finally, an experimental investigation on four substructure joints with CFDST columns for validation purposes was carried out to capture the connection details. The predicted results derived from the mechanical models coincided well with the experimental results. It is demonstrated that the proposed mechanical model is capable of evaluating the complete moment-rotation relationships of blind bolted CFDST column composite connections.

• Journal of the Korean Solar Energy Society
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• v.36 no.4
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• pp.1-9
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• 2016

The purpose of this study was to compare heat shading performance of various blind types in summer. 4 types of blinds were employed and the results are summarized as follows: 1) There were significant differences in indoor thermal environment and heat shading performance between different heat shading devices, and functional blinds demonstrated relatively superior heat shading performance. 2) Indoor long wave radiation influx measures were lowest for the coating roll blind (Blind B), followed by the coating venetian blind (Blind C), the venetian blind (Blind A), the roll blind, and not having any blinds at all. 3) Such examination results carry implications to reduce cooling load and enhance the indoor environment.

• Journal of the Optical Society of Korea
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• v.7 no.3
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• pp.202-206
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• 2003

In this paper, minimum mean-squared-error(MMSE) and blind equalization schemes were employed to improve bit-error-rate(BER) and to reduce inter-symbol interference(ISI) generated during storage and retrieval processes of two-dimensional data in a digital holographic data storage system. We explained methods for designing and applying MMSE and blind equalization to improve BER in a digital holographic data storage system. From experimental evaluations, we compared the BER performances of MMSE and blind equalization and we showed that the BER performances of MMSE and blind equalization were improved significantly compared with those before equalization.

• Journal of the Korea Society of Computer and Information
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• v.18 no.7
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• pp.85-92
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• 2013

In this paper, on the basis of Guilin Wang's proxy signature scheme and the Schnorr blind signature, we propose a secure proxy blind signature scheme. A proxy blind signature scheme is a digital signature scheme which combines the properties of a proxy signature and a blind signature scheme. Guilin Wang proposed a provably secure proxy signature scheme, which is based on a two-party Schnorr signature scheme. Also, using the proposed proxy blind signature scheme, we propose the proxy agent system for the electronic voting. We show the proposed scheme satisfies the security properties of both the blind signature and the proxy signature scheme and is efficient and optimal proxy blind signature scheme.

• Steel and Composite Structures
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• v.36 no.4
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• pp.447-462
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• 2020

The paper aims to investigate the mechanical mechanism and seismic effect of stiffeners in blind bolt endplate connection to CFST column. A precise 3D finite element model with considering the cyclic properties of concrete and steel materials was established, and the efficiency was validated through monotonic and cyclic test data. The deforming pattern and the seismic performance of the unstiffened and stiffened blind bolt endplate connections were investigated. Then a parametric analysis was conducted to analyze the contribution of stiffeners and the joint working behaviors with endplate under cyclic load. The joint stiffness classifications were compared and a supplement stiffness classification method was proposed, and the energy dissipation ability of different class connections were compared and discussed. Results indicated that the main deformation pattern of unstiffened blind bolt endplate connections was the local bending of end plate. The vertical stiffeners can effectively alleviate the local bending deformation of end plate. And influence of stiffeners in thin endplate and thick endplate was different. Based on the stiffness of external diaphragm welded connection, a more detailed rigidity classification was proposed which included the pin, semi-rigid, quasi-rigid and rigid connection. Beam was the main energy dissipation source for rigid connection. For the semi-rigid and quasi-rigid connection, the extended endplate, stiffeners and steel beam would all participate in the energy dissipation.

• ETRI Journal
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• v.32 no.2
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• pp.333-335
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• 2010

This letter proposes a non-coherent blind time-of-arrival (TOA) estimation scheme for impulse radio ultra-wideband systems. The TOA estimation is performed in two consecutive phases: the Rayleigh-quotient theorem-based coarse-signal acquisition (CSA) and the iterative-threshold-test-based fine time estimation (FTE). The proposed scheme serves in a blind manner without demanding any a priori knowledge of the channel and the noise. Analysis and simulations demonstrate that the proposed scheme significantly increases the signal detection probability in CSA and ameliorates the TOA estimation accuracy in FTE.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.537-544
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• 2011

Tactile acuity was assessed in groups of control, blind, deaf, and blind caused by complication to investigate the effective tactile stimuli on tactile sensory substitution studies when tactile display is applied to persons with sensory loss of vision or hearing. Two-point discrimination and grating resolution were assessed by compass and JVP dome, respectively, in the hand, arm, neck, lumbar, and knee. In two-point discrimination by compass, control group showed the highest sensitivity in fingers among assessed body areas but did not show any significant difference between male and female. Blind group and deaf group compared to control group did not show any significant difference in fingers but showed lower sensitivity in arm and knee. In grating resolution by JVP dome, control group did not show any significant difference among five fingers as well as between male and female. Blind group showed higher sensitivity in five fingers compared to control group, but deaf group did not show any significant difference from control group. Blind caused by complication group showed lower sensitivity in two-point discrimination and grating resolution compared to control group and blind group. These results suggest that the body area and method of tactile stimulation, and difference in tactile acuity depending on underlying disease of sensory loss should be considered when tactile display is applied for sensory substitution.

• ETRI Journal
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• v.26 no.2
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• pp.101-111
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• 2004

This paper presents a near-optimum blind decision feedback equalizer (DFE) for the receivers of Advanced Television Systems Committee (ATSC) digital television. By adopting a modified trellis decoder (MTD) with a trace- back depth of 1 for the decision device in the DFE, we obtain a hardware-efficient, blind DFE approaching the performance of an optimum DFE which has no error propagation. In the MTD, the absolute distance is used rather than the squared Euclidean distance for the computation of the branch metrics. This results in a reduction of the computational complexity over the original trellis decoding scheme. Compared to the conventional slicer, the MTD shows an outstanding performance improvement in decision error probability and is comparable to the original trellis decoder using the Euclidean distance. Reducing error propagation by use of the MTD in the DFE leads to the improvement of convergence performance in terms of convergence speed and residual error. Simulation results show that the proposed blind DFE performs much better than the blind DFE with the slicer, and the difference is prominent at the trellis decoder following the blind DFE.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.3
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• pp.31-40
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• 2022

PURPOSE: This study was conducted to investigate the effects of postural control training using a visual blind board, on head control, trunk control, and the sitting abilities of children with moderate-to-severe cerebral palsy. METHODS: Ten children with moderate to severe cerebral palsy participated in this study. Postural control training with a visual blind board was given for 40 minutes per session, 3 times a week for 4 weeks (12 sessions). Before and after the intervention, head control, trunk control, and sitting abilities were quantified using the head control scale, Korean version-trunk control measurement scale, and the sitting part of the Korean version-gross motor function measure-88, respectively. RESULTS: Postural control with the visual blind board significantly improved the head control ability of children with moderate to severe cerebral palsy (p = .015). Their trunk control abilities also showed significant improvement after the intervention (p = .016). However, their sitting ability did not show a significant change. CONCLUSION: These results showed that postural control training using a visual blind board is effective in improving the head and trunk control abilities of children with cerebral palsy. Further studies with suitable sample sizes and control groups are needed to reach a conclusion about the use of postural control training with visual blind boards for improvement of postural control of children with moderate to severe cerebral palsy.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.225-228
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• 2005

According to a popularization of the Internet and digital lifestyle, digital watermarks have been proposed for protection of copyrighted multimedia content. In blind watermark detection, which an original image is not provided, robustness against geometric distortion and compression remains challenging. In this paper, we propose a new perceptual blind discrete wavelet transform - discrete Fourier transform (DWT-DFT) composite watermarking scheme that is robust against both general linear transform and JPEG compression. This algorithm constructs an image-dependent watermark in the most significant DWT coefficients, which is determined by using a hierarchical tree structure. Strength of watermark is determined from a just-noticeable difference (JND) profile of a perceptual model. Furthermore, a desired template is inserted into DFT domain of the watermarked image. In new manner, a cross-ratio of four collinear points is used for detecting the template. Experimental results have showed that the proposed scheme is robust against general linear distortion, JPEG compression and various general kinds of attacks in the Stirmark 3.1 watermark evaluation tool.