Kyungnam University

Design guidance for headed-bar development remains uncertain for large-diameter bars at cutoff points, where bar termination increases anchorage demand and confinement is often limited. This study quantified the anchorage behavior of 43 and 57 mm headed bars and established a regression-based strength model grounded in a splitting-controlled bond–bearing mechanism. Nineteen reinforced concrete beam specimens were tested under four-point loading configured to place the bending-moment inflection point at the head location. The primary variables were the development length (ldt = 12–28db), concrete compressive strength (fc′ = 42 and 70 MPa), clear side cover, clear spacing, and transverse reinforcement index (Ktr/db = 0–2.0). All the specimens failed by splitting prior to bar yielding, characterized by longitudinal cracking along the development region and cover spalling near the head. The anchorage strength increased with concrete compressive strength and development length and was most strongly enhanced by transverse reinforcement (up to ~60%). At failure, the bond contributed 70–86% of the developed stress, while the head-bearing contribution increased with confinement. Existing ACI 318-19 and KDS-2021 provisions were generally unconservative, particularly for unconfined specimens. The proposed bond–bearing model showed a close agreement with the test database (mean test/prediction = 0.99; COV = 4.72%) within stated parameter limits.

The global aging population is rapidly increasing, with associated declines in motor and cognitive function leading to higher fall risk and reduced independence. Exercise interventions improve strength, balance, and cognition, but accessibility barriers remain. While technology assistance programs are promising, they often lack clinical perspectives, are difficult to adapt, and lack features that encourage participation. This study aimed to develop and evaluate a motion recognition-based interactive training program designed by a physical therapist to enhance motor function and physical fitness in older adults. Twenty-eight community-dwelling older adults (≥65 years) were randomly assigned to an experimental group (n=13) or control group (n=15). The experimental group completed three weekly sessions of motion recognition exercises with adaptive feedback for 4 weeks, while the control group performed stretching. Outcomes included task performance metrics (attempts, corrections, accuracy) automatically recorded by the program and fitness measures from the senior fitness test. The experimental group showed significant increases in attempts and corrections across all body parts, with notable accuracy improvement in head movements (P<0.05). Flexibility significantly improved between groups, while both groups improved in lower extremity strength and endurance. No significant changes were observed in upper limb strength or agility. A clinically designed, motion recognition-based interactive program enhanced motor performance and flexibility in older adults. Incorporating adaptive difficulty and real-time feedback, it shows potential as a scalable, cost-effective digital intervention for promoting active aging.

This paper presents a bistatic 60 GHz frequency-modulated continuous-wave (FMCW) radar system for non-contact heart rate monitoring, utilizing high-gain Fabry–Perot cavity (FPC) antennas at both the transmitter and receiver. Each FPC antenna integrates a partially reflective surface (PRS) and a metallic ground plane to form a resonant cavity. Compared to conventional patch arrays of the same aperture, the FPC antenna improves the antenna gain from 4.1 dBi to 8.1 dBi at the transmitter and from 3.9 dBi to 7.8 dBi at the receiver, resulting in an overall link budget enhancement of approximately 7.9 dB. This dual high-gain configuration theoretically increases the maximum detection range by a factor of 2.48. The proposed radar system was implemented and experimentally validated under indoor conditions using both calibration targets and human participants. Active measurement results confirm that the bistatic radar equipped with FPC antennas extends the reliable heart rate detection distance by approximately 2.27 times compared to a conventional system, closely matching the theoretical prediction. These results confirm the practicality and effectiveness of FPC antennas in extending both the range and reliability of millimeter-wave vital sign detection systems.

IntroductionWhile exercise interventions are widely used for sarcopenia management, the comparative efficacy of different non-invasive treatments remains unclear. This network meta-analysis evaluated five interventions (aerobic training, resistance training, aerobi-resistance training, whole-body electrical stimulation, and electrical stimulation with protein supplementation) on body composition, physical function and quality of life in elderly sarcopenia patients.MethodsSix databases, including PubMed, Embase and Web of Science, were systematically searched, and 22 randomized controlled trials with a total of 1062 elderly patients with sarcopenia were finally included. The outcome indicators were those related to the evaluation of body composition, physical function and quality of life. Net meta-analysis was performed using Stata 17.0 to assess the relative effectiveness of each intervention and to test the consistency of direct and indirect evidence.ResultsES&P (SMD = −3.33, 95% CI [−4.23, −2.44], p < 0.00001) and AT (SMD = −1.31, 95% CI [−1.83, −0.79], p < 0.00001, I2 = 58%) demonstrated significant effects in terms of fat reduction, RT achieved a significant effect in terms of muscle gain (SMD = 0.50, 95% CI [0.08, 0.91], p < 0.05, I2 = 42%), RAT was the most effective in terms of strength gains (SMD = 0.51, 95% CI [0.05, 0.98], p < 0.05, I2 = 0%), and RAT also demonstrated a favorable effect in terms of improving quality of life (SMD = 1.42, 95% CI [0.13, 2.70], p < 0.05, I2 = 55%).ConclusionES & P and AT have good effect on fat reduction, RT has the best effect on increasing muscle, RAT is the most effective in improving strength, and AT is the best in improving quality of life. Different treatments have different effects on functional indicators, and clinics should personalize the selection of different interventions according to the patient’s condition and combine multiple interventions to achieve the best recovery results.

Structural equation modeling (SEM) has become one of the most commonly used tools in management research, yet researchers frequently encounter methodological challenges that can compromise the validity of their findings. This symposium presents three methodological papers that offer empirically validated solutions to common challenges in latent variable modeling. The paper by Williams, Culpepper, and Castille evaluates competing approaches for model selection using the RMSEA-P fit index, providing evidence-based guidance for choosing between Traditional and Sequential Model Comparison strategies. Next, Choi and colleagues introduce a novel Pseudo-Augmentation strategy to address underidentification issues in bifactor predictive models, demonstrating its effectiveness through Monte Carlo simulations and empirical examples. Finally, Hanna presents a comprehensive empirical investigation of competing parceling approaches for multidimensional constructs, illuminating how parceling decisions impact model fit. Together, these works provide additional methodological insight into common SEM challenges by providing researchers with empirically supported strategies for improving model selection, addressing identification issues, and making informed decisions about parameter reduction in structural equation modeling. A Comparison of Latent Variable Model Selection Approaches Using the RMSEA-P Author: Larry J. Williams; Texas Tech University Author: Steven Culpepper; Author: Christopher Castille; Nicholls State University A Pseudo-Augmentation Strategy to Address Underidentification in Bifactor Predictive Models Author: Jinsoo Choi; University of Illinois at Urbana-Champaign Author: Bo Zhang; University of Illinois at Urbana-Champaign Author: Susu Zhang; University of Illinois at Urbana-Champaign Author: Yonguk Park; Kyungnam University A Test of Parceling Approaches with Multidimensional Constructs and Their Model Fit Consequences Author: Andrew A. Hanna; University of Nebraska-Lincoln

This paper presents the design of an orientation-independent non-invasive glucose sensor based on a meta-structured antenna. The sensor is designed for blood glucose measurement through fingertip placement on the sensor and features a mushroom structure to generate zeroth-order resonance (ZOR). Moreover, the mushroom structure has a hexagonal patch for orientation-independent non-invasive sensing. The operating frequency of the sensor is 4 GHz, and the overall size is 55 mm × 55 mm. In our study, the range of glucose concentration is from 50 to 250 mg/dL, with a step size of 50 mg/dL. The simulated and measured results show a linear relationship between the resonance frequency and the glucose concentration in the solution, and the linear shift of 0.352 MHz/mg/dL has been observed. On the other hand, the reflection coefficient level variation is a nonlinear function of the glucose concentration for the considered concentration ranges. Mathematical models describing the sensor response across all fingertip orientations are developed for the designed sensor using the regression analysis (R2 ≥ 0.993) relating the glucose concentration to the measured resonance frequency and reflection coefficient level. While the reflection coefficient shows a nonlinear response, the resonance frequency exhibits a strong linear correlation with glucose concentration, making it a more reliable parameter for accurate prediction in the proposed sensing model.

In this paper, a dual-band circularly polarized (CP) shared-aperture microstrip patch antenna with a high frequency ratio of 4.1 is presented for S-/X-band satellite communications. The unit cell of the designed antenna is composed of a single perforated S-band trimmed patch and four X-band trimmed patches configured in a 2 × 2 array. The S- and X-band patches are interlaced, thus sharing their apertures within the same layer, which enhances isolation between the two bands and prevents the degradation of CP characteristics. The antenna was designed and optimized for the S-band frequency range of 1.9–2.05 GHz and the X-band frequency range of 7.8–9 GHz. To verify feasibility, the performance of the proposed antenna was measured in a full anechoic chamber. The measured results showed good agreement with the simulated results. The -10 dB impedance bandwidths of the S- and X-band antennas were 7.8% and 13.5%, respectively, while their measured 3-dB axial ratio bandwidths were 2% and 3.9%, respectively. Furthermore, the unit cell antenna achieved left-handed circularly polarized peak gains of 5.7 dBic at 2.02 GHz and 11.6 dBic at 8.28 GHz.