• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1395-1398
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• 1997

Flexible parts comparing with rigid parts can be deformed by contact force during assembly. for successful assembly, information about their deformation as well as possible misalignment between mating parts is essential. Howecer, because of the complex relationship between parts deformation and reaction forces, it is difficult to acquire all required information from the reaction forces alone. In this paper, we measure parts deformation and misalignments by using the visual sensing system presented for flexible parts assembly. Experimental results show that the system can be effectively used for detecting parts deformation and misalignments between mating parts.

• Transactions of the Society of Information Storage Systems
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• v.6 no.2
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• pp.47-51
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• 2010

We investigate misalignment characteristics of 5/8 modulation code for holographic data storage. The 5/8 modulation code does not have any isolated patterns that is the most unwanted problem for holographic data storage. As the results, the 5/8 modulation code showed a strong side of misalignments, and the code has the best performance among uncoded, 5/9, and 6/8 modulation codes when there are large misalignments.

• The Journal of Korean Medicine
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• v.28 no.3 s.71
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• pp.45-56
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• 2007

Objectives : We investigated the possibility of cervical spine misalignment caused by scalenus anticus syndrome to find out how it affects cervical spine misalignments. Methods : 28 patients with scalenus anticus syndrome (sample group), along with 21 participants without neck pain (control group), who attended the Dept. of Oriental Rehabilitation Medicine, College of Oriental Medicine, Dong-guk University from the 20th of June to the 30th of November, 2006 were investigated. After researching misalignments through neutrality, flexion and extension lateral x-ray examination views, we measured the difference of each length of cervical spine misalignment. We analyzed the relationships among the neutrality lateral, flexion lateral and extension lateral positions. Results : We found with statistical significance that there were differences in length of cervical spine misalignments between the sample and control groups. Furthermore, we found that C3 and C4 vertebra bodies were shown in lateral neutrality position, only C3 vertebra body in flexion lateral position, and C2, C3, and C4 vertebra bodies in extension lateral position. Conclusions : It is considered that scalenus anticus syndrome could increase cervical spine misalignment which could be a factor in causing cervical spine disease.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.10
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• pp.809-814
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• 2012

We propose an adaptive threshold detector algorithm for multi-level holographic data storage based on the expectation-maximization (EM) method. In this paper, the signal intensities that are passed through the four-level holographic channel are modeled as a four Gaussian mixture with unknown DC offsets and the threshold levels are estimated based on the maximum likelihood criterion. We compare the bit error rate (BER) performance of the proposed algorithm with the non-adaptive threshold detection algorithm for various levels of DC offset and misalignments. Our proposed algorithm shows consistently acceptable performance when the DC offset variance is fixed or the misalignments are lower than 20%. When the DC offset varies with each page, the BER of the proposed method is acceptable when the misalignments are lower than 10% and DC offset variance is 0.001.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.7
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• pp.841-847
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• 1999

For successful assembly of flexible parts, informations about their deformation as well as possible misalignments between the holes and their mating parts are essential. Such informations can be acquired from visual sensors. For robotic assembly, the corrective assembly motion to compensate for such misalignments has to be determined from the measured informations. However, this may not be simply derived from the measured misalignment alone because the part deformation progressively occurs during misalignment compensation. Based on the analysis of flexible parts assembly process, this paper presents a neural net-based inference system that can infer the complex relationship between the corrective motion and the measured information of parts deformation and misalignments. And it verifies the performance of the implemented inference system. The results show that the proposed neural net-based misalignment compensation algorithm Is effective in compensating for the lateral misalignment, and that it can be extended to the assembly tasks under more general conditions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.2 s.332
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• pp.17-22
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• 2005

This paper presents our investigation for the effect of symbol timing errors in orthogonal frequency division multiple access (OFDMA) uplink systems. We express the symbol timing errors between users as the symbol timing misalignments with respect to the desired user. Then, we derive an explicit expression of the average effective signal-to-interference-plus-noise ratio. (SINR) as a function of the maximum value of the symbol timing misalignments. Based on the resulting SINR degradation, we evaluate the SINR gain with guard subcarriers in order to mitigate the effect of the symbol timing misalignments.

• Journal of Korean Society of Steel Construction
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• v.16 no.4 s.71
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• pp.479-492
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• 2004

When U-ribs of steel deck plates are connected at the field, overhead welding should be done with backing strips. Misalignments may occur and lead to eccentric moments as well as high stress concentrations at welded joints. In this study, stress analyses and fatigue tests were carried out. Stress analyses for U-ribs' welded joints with backing strips were performed with different misalignments, root shapes, root gaps, and backing strip sizes. From the stress analyses, the stress concentration factors increased with increasing misalignments and root gaps. With the fixed misalignments and root gaps, the stress concentration factors obtained in the case of the semi-circle root shape were lower than those in the case of the right-angle root shape. It was verified that backing strip sizes have little influence on stress concentration factors. The fatigue tests for U-ribs' welded joints with backing strips indicated that increased misalignments shorten fatigue life drastically and cracks usually initiate at the root of the base metal and are propagated to the weld bead surface. Based on the results of the stress analyses, root-shape control methods were developed to mitigate stress concentration by changing welding condition control, radius curvature, and flank angle.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.36-44
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• 1995

For a parabolic reflector antenna, a simple method is presented for computing efficiently the average power pattern degradations caused by the surface roughness of the reflector and misalignments between the reflector and the feed. In this procedure, both nonuniform surface errors and nonuniform illuminations are employed. The assumptions to derive the expressions are that in each annular region of the antenna, the rms value of the surface roughness is known, and in a zone in a annular region, the phase error by misalignments is constant, and can be taken to its value at the center of the zone. Detailed parametric studies are performed with derived expressions to determine the effects of those errors and illumination tapers on parameters such as gain and sidelobe levels.

• Journal of Korean Society of Steel Construction
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• v.8 no.3 s.28
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• pp.13-20
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• 1996

With the adoption of welded joints rather than bolted joints, we investigate the fatigue strength and the fatigue crack initiation of U-type trough rib and welded specimen with misalignment in a steel deck plate. The stress concentration factor of welded specimens with a misalignment is also verified by a finite element method. The main conclusions obtained from this study are as follows Experimental results of full-scaled U-type trough rib models have indicated that fatigue life depends on misalignments of welded joints in steel deck plate ; The more misalignments are, the less the fatigue life is. It has also shown that fatigue crack propagates from the welded root to the bead surface. We have also obtained the same results from both the fatigue test of welded specimens with a misalignment and the stress analysis of a finite element method.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.155-160
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• 2008

Using a three-dimensional (3-D) FE analyses, this paper provides the shape optimization of the standard test specimen for the torsion test, as well as a method for analyzing effects of misalignment under the angular and concentric misalignment. For verification, FE analysis is performed, which is designed for the perfectly full-model. To optimize the design shape of the torsion-controlled fatigue test specimen, we performed sensitivity analysis using shape parameters. Additionally, two kinds of misalignment (angular misalignment and concentric misalignment) are applied to the circular and tubular specimens to show effects of misalignments in the FE analysis. The present results will provide valuable information for designing shafts for every kind of mechanical system under torsional force.