• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.10
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• pp.3458-3478
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• 2022

Automatic modulation recognition is the core algorithm in the field of modulation classification in communication systems. Our investigations show that deep learning (DL) based modulation recognition techniques have achieved effective progress for multiple-input multiple-output (MIMO) systems. However, network complexity is always an additional burden for high-accuracy classifications, which makes it impractical. Therefore, in this paper, we propose a low-complexity dimensional interactive lightweight network (DilNet) for MIMO systems. Specifically, the signals received by different antennas are cooperatively input into the network, and the network calculation amount is reduced through the depth-wise separable convolution. A two-dimensional interactive attention (TDIA) module is designed to extract interactive information of different dimensions, and improve the effectiveness of the cooperation features. In addition, the TDIA module ensures low complexity through compressing the convolution dimension, and the computational burden after inserting TDIA is also acceptable. Finally, the network is trained with a penalized statistical entropy loss function. Simulation results show that compared to existing modulation recognition methods, the proposed DilNet dramatically reduces the model complexity. The dimensional interactive lightweight network trained by penalized statistical entropy also performs better for recognition accuracy in MIMO systems.

• Journal of electromagnetic engineering and science
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• v.19 no.2
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• pp.115-121
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• 2019

This paper presents the effects of the position of the split of a split-ring resonator (SRR) on the performance of a composite broadband printed dipole antenna. The antenna is made of two printed dipole arms enclosed by two rectangular and identically printed SRRs. One dipole arm and the SRR are printed on the top side of the substrate, while the other dipole arm and SRR are printed on the bottom side of the same substrate. By changing the position of the split on the SRR, different antenna characteristic values are obtained, namely, for impedance bandwidth and radiation patterns. The split position is thus a critical parameter in antenna design, because it influences the antenna's major performance immensely. Different split positions and their consequences for antenna performance are demonstrated and discussed. The antenna generates linearly polarized radiations, and it is computationally characterized for broadband characteristics. The optimized compact antenna has overall dimensions of 9.6 mm × 74.4 mm × 0.508 mm (0.06λ × 0.469λ × 0.0032λ at 1.895 GHz) with a measured fractional bandwidth of 60.31% (1.32 to 2.46 GHz for |S₁₁| <-10 dB) and a radiation efficiency of >88%.

• Korean Journal of Childcare and Education
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• v.20 no.3
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• pp.43-66
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• 2024

Objective: The purpose of this study is to investigate the direct effect of organizational health, as perceived by childcare teachers, on their turnover intention, and to examine the mediating effect of work-life balance on the relationship between these two variables. Methods: The subjects of this study were 345 childcare teachers working at 45 childcare centers located in Gyeonggi-do. Descriptive statistics, factor analysis, reliability analysis, and Pearson correlation analysis were performed using SPSS 21.0. Additionally, the mediating effect was verified using the PROCESS Macro, and bootstrapping was performed to confirm the significance of the indirect effect. Results: First, there was a significant negative correlation between the organizational health of childcare centers, the turnover intention of childcare teachers, and their work-life balance. Second, it was found that work-family balance completely mediated the relationship between the organizational health of childcare centers and the turnover intention of childcare teachers, while work-leisure balance and work-growth balance partially mediated the relationship between these two variables. Conclusion/Implications: This study provides essential data for examining ways to lower the turnover intention of childcare teachers by addressing both individual and organizational dimensions.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.285-292
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• 2024

Physiological devices and immersive technologies are crucial innovations being implemented for construction safety. Physiological devices provide insights into the wellbeing of workers while immersive technologies have a potential to simulate or enhance construction environments. These two technologies present numerous benefits for construction safety and have been extensively implemented in various dimensions. In addition to the individual benefits of these two technologies, combining them presents more opportunities for construction safety research and numerous studies have been conducted using this approach. However, despite promising results achieved by studies which have used this technological combination, no review has been conducted to summarize the findings of these studies. This review therefore summarizes studies that have combined immersive technologies with physiological monitoring for construction safety. A systematic approach is employed, and 24 articles are reviewed. This review highlights four safety aspects which have been explored using a combination of immersive technologies and physiological monitoring. These aspects are (1) Safety training and evaluation (2) Hazard identification (3) Attention assessment and (4) Cognitive strain assessment. In addition, there are three main directions for future research. (1) Future studies should explore other types of immersive technologies such as immersive audio (2) Physiological reactions to hazard exposure should be studied and (3) More multi-physiological approaches should be adopted.

• Phonetics and Speech Sciences
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• v.16 no.3
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• pp.7-23
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• 2024

Previous studies have highlighted the linguistic divergence between North and South Korean varieties. Although acoustic differences between North and South Korean in vowel production have been prominently observed, the vowel production in the standard varieties of Pyongyang North Korean (NK) and Seoul South Korean (SK) has had limited investigation. This study aims to explore the phonetic differences in vowel production between NK and SK speakers across two speech styles: careful and conversational speech. We analyzed a total of 13,370 vowels from each of 22 younger NK and SK speakers (16 females and 6 males in each group). Our findings reveal significant differences in the production of the vowels [æ], [ʌ], and [o] between the two varieties. Specifically, NK speakers maintained a distinction in height between the [e]-[æ] pair, a contrast that was not observed among SK speakers. Additionally, in NK, the [ʌ]-[o] pair showed considerable overlap (vowel merger) in both height and backness dimensions. These results shed light on the phonetic divergence between NK and SK varieties, offering insights into the acoustic features of NK vowel production. In further study, this understanding is crucial for supporting adaptation of NK refugees from the perspective of second dialect acquisition in South Korea.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.1
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• pp.3-8
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• 2006

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module optimal design technique and horizontal split of die insert were investigated for determining appropriate dimensions of components of multi-former die set. Results obtained, using the modules, enable the design and manufacture of a die set for a multi-former to be more efficiently performed.

• Structural Engineering and Mechanics
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• v.52 no.2
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• pp.369-389
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• 2014

Two-layer coupled or composite beams with discrete shear connectors of finite dimensions are commonly encountered in pre-fabricated construction. This paper presents the development of simplified closed-form solutions for such type of coupled beams for practical applications. A new coupled beam element is proposed to represent the unconnected segments in the beam. General solutions are then developed by an inductive method based on the results from the finite element analysis. A modification is subsequently considered to account for the effect of local deformations. For typical cases where the local deformation is primarily concerned about its distribution over the depth of the coupled beam, empirical modification factors are developed based on parametric calculations using finite element models. The developed analytical method for the coupled beams in question is simple, sufficiently accurate, and suitable for quick calculation in engineering practice.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.431-438
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• 1999

An assessment of liquefaction potential is made in principle by comparing the shear stress induced by earthquake to the liquefaction strength of the soil. In this study, a modified method based on Seed and Idriss theory is developed for evaluating liquefaction potential. The shear stress in the ground can be evaluated with seismic response analysis and the liquefaction strength of the soil can be investigated by using cyclic triaxial tests. The cyclic triaxial tests are conducted in two different conditions in order to investigate the factors affecting liquefaction strength such as cyclic shear stress amplitude and relative density. And performance of the modified method in practical examples is demonstrated by applying it to liquefaction analysis of artificial zones with dimensions and material properties similar to those in a typical field. From the result, the modified method for assessing liquefaction potential can successfully evaluate the safety factor under moderate magnitude(M=6.5) of earthquake.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.185-189
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• 2009

Recently, ultra high strength products can be manufactured by the hot press forming process of Boron steel in automotive and electronics industries. In order to get high strength, the hot press forming should be accompanied by quenching process inducing phase transformation. There are several types of the hot press forming processes according to the quenching method, water quenching and die quenching, etc. In the study, the process was numerically and physically simulated to compare the two types of quenching processes, and then the strength, hardness and dimensions of the products were compared with try-outs.

• Archives of Pharmacal Research
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• v.7 no.2
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• pp.137-139
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• 1984

The molecular structure of (+)-6-Me hoxy-.alpha.-methyl-2-naphthaleneacetic acid (Naproxen), $C_{14}H_{14}O_{ 3}$, was determined by X-Ray diffraction technique. Naproxen crystallized in $P2_1$ with two molecules on the unit cell of dimensions a = 7.855, b = 5.783, c = 13.347$\AA$ and $\beta$ = $93.9^{\circ}$