• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2511-2520
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• 2011

This paper describes the parameter adjustment method of fuzzy membership function to improve the performance of multi-sensor fusion system using adaptive fuzzy-Kalman filter and cross-validation. The adaptive fuzzy-Kanlman filter has two input parameters, variation of accelerometer measurements and residual error of Kalman filter. The filter estimates system noise R and measurement noise Q, then changes the Kalman gain. To evaluate proposed adaptive fuzzy-Kalman filter, we make the two-axis AHRS(Attitude Heading Reference System) using fusion of an accelerometer and a gyro sensor. Then we verified its performance by comparing to NAV420CA-100 to be used in various fields of airborne, marine and land applications.

• Journal of Korean Society of Steel Construction
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• v.12 no.3 s.46
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• pp.239-250
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• 2000

This study investigates the mechanical behavior on trough rib to crossbeam joint in orthotropic steel plate decks, specially emphasizing on the effect of diaphragm inside trough rib on the fatigue behavior of slit by static and fatigue tests. In particular, the effects of diaphragm on in-plane stress and out-of-plane stress, stress concentration, propagation of fatigue cracks at the silt are studied. With the result of experiment and numerical analysis, we have estimated the fatigue strength using the nominal stress and hot-sport stress. The details with diaphragm have occurred about 50% stress reduction at trough rib part of trough rib to crossbeam joint than the detail without diaphragm, however, the lower parts of crossbeam have occurred much more stress. Initial crack size or slit have an considerable influence on the propagation of fatigue cracks due to V-notch. The fatigue strength category of the details without diaphragm has higher value than fatigue limit, whereas that of the details with diaphragm is estimated lower than fatigue limit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1246-1254
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• 2012

The South Korea has the highest overall smoking rates of male among the thirty member-countries in the Organization for Economic Cooperation and Development. This study was performed to determine the association between amount of smoking and self-reported voice problem in Korean adult population using national survey data. Data were drawn from the Korea National Health and Nutritional Examination Survey 2008. Subjects were 3,600 persons (1,501 male, 2,099 female) aged 19 years and older living in the community. Adjusting for covariates (age, sex, education, income, longest occupation, alcohol drinking, pain and discomfort during the last 2 weeks), Severe smoke (>40.5-55.5 pack year), more than 20 cigarettes per day were independent risk factors for self-reported voice problem. It was found that the number of cigarettes smoked per day (CPD) the proportional increased in risk of voice disorders. These findings suggest that the investigation of CPD are required for effective screening of voice disorder.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.8
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• pp.684-692
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• 2016

In this paper, a non-offset longitudinal shunt slot excited by an asymmetry compound iris on the broad wall of a rectangular waveguide is presented as an element for a waveguide slot-array antenna(WSAA). By properly adjusting the iris dimension, a resonance of the slot at a desired frequency can be achieved. The proposed resonant slot has some advantageous properties, such as a wide range of normalized resonant conductance, and minimum change of phase in the waveguide at the resonance. In addition, when the slots are arrayed for a waveguide slot antenna, the unwanted cross-polarization level can be reduced because each slot is placed in a straight line. A $8{\times}1$ WSAA with -20 dB side-lobe level(SLL) is designed, fabricated, and tested experimentally. The measured results are well agreed with the simulated ones and have an SLL of -18.13 dB and a cross-polarization level of -48.85 dB at 9.41 GHz, which was improved by about 15 dB of that of the conventional longitudinal slot array antenna.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.2
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• pp.140-148
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• 2002

Anisotropic elastic constants of Zr-2.5Nb pressure tube materials were determined by a high temperature resonant ultrasound spectroscopy (RUS). The resonant frequencies were measured using alumina wave-guides and wide band ultrasonic transducers in a small furnace. The rectangular parallelepiped specimens were fabricated along with the axial, radial and circumferential direction of the pressure tube. A nine elastic stiffness tensor for orthotropic symmetry was determined in the range of room temperature ${\sim}500^{\circ}C$. As the temperature increases, the elastic constant tensor, cij gradually decreases. Higher elastic constants along the transverse direction compared to those along the axial or radial direction are similar to the case of Young's modulus or shear modulus. A crossing of shear elastic constants along axial direction and radial direction was observed near $150^{\circ}C$. This fact corresponds to the crossing of c44 and c66 of single crystal zirconium.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.81-98
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• 2002

This paper documents the development of a bi-objective(minimizing delays and Queue lengths) cycle-free signal timing length model using Genetic Algorithm. The model was embodied using MATLAB. the language of technical computing. A special feature of this model is its ability to concurrently manage delays and queue lengths of turning movement concurrently. The model produces a cycle-free signal timing(cycles and green times) for each intersection on the cycle basis. Appropriate offsets could be also accomplished by applying cycle-free based signal timings for respective intersections. The model was applied to an example network which consists of four intersections. The result shows that the model produces superior signal timings to the existing signal timing model in terms of managing delays and queue lengths of turning movements.

• Journal of Korean Society of Steel Construction
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• v.28 no.4
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• pp.231-242
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• 2016

Earthquake resistance of RC column-steel beam (RCS) joints with simplified details were studied. Simplified details are necessary for large columns to improve the productivity and constructability. To strengthen the beam-column joint, the effects of transverse beams, studs, and U-cross ties were used. Four 2/3 scale interior RCS connections were tested under cyclic lateral loading. The specimens generally exhibited good deformation capacity exceeding 4.0% story drift ratio after yielding of both beam and beam-column joint. Ultimately, the specimens failed by shear mechanism of the joint panel. The test strengths were compared with the predictions of existing design methods.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.103-108
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• 2020

Recently, consumer demand for safe but minimally processed food has rapidly increased. For this reason, many food processing industries are applying hurdle technology to enhance food safety, extend shelf life, and make foods appear minimally processed. Meanwhile, studies have shown that a treatment (stress) meant to inactivate foodborne pathogens may trigger adaptation mechanisms and could even offer cross protection against subsequent treatments. Also, certain routine farm practices such as antibiotic and herbicide use could result in the development of antibiotic-resistant pathogens. Such bacteria may be tolerant to food processing-associated stress and be more likely to remain viable in processed foods. In this review, we discuss the correlation between food processing-associated stress and antibiotic resistance. We also discuss molecular mechanisms such as the use of sigma factors, SOS response pathways and efflux pumps as means of cross protection against antimicrobial compounds and other food processing-associated stresses.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.711-721
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• 2004

The aim of this study is to clarify whether frequency and/or severity of extreme climate events have changed significantly in Korea during recent years. Using the best available daily data, spatial and temporal aspects of ten climate change indicators are investigated on an annual and seasonal basis for the periods of 1954-1999. A systematic increase in the $90^{th}$ percentile of daily minimum temperatures at most of the analyzed areas has been observed. This increase is accompanied by a similar reduction in the number of frost days and a significant lengthening of the thermal growing season. Although the intra-annual extreme temperature range is based on only two observations, it provides a very robust and significant measure of declining extreme temperature variability. The five precipitation-related indicators show no distinct changing patterns for spatial and temporal distribution except for the regional series of maximum consecutive dry days. Interestingly, the regional series of consecutive dry days have increased significantly while the daily rainfall intensity index and the fraction of annual total precipitation due to events exceeding the $95^{th}$ percentile for 1901-1990 normals have insignificantly increased.

• Composites Research
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• v.31 no.4
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• pp.156-160
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• 2018

In this paper, evaluation method of structural integrity for cone-type composite lattice structures with hexagonal cell was conducted. A finite element analysis was used to evaluate the structural integrity of cone-type composite lattice structure. The finite element model for evaluation of structural integrity was generated using solid element. In order to consider the difference in mechanical properties between intersection and non-intersection part, the mechanical properties were applied considering the fiber volume fraction of each part. Compression test of cone-type composite lattice structure were conducted for verification of evaluation method of structural integrity. The analysis result showed 2% errors in displacement and good agreement with test result.