Journal of the Korean Physical Society最新文献

{"title":"Deterministic reconstruction of tennis serve mechanics: from aerodynamic constraints to internal torques via rigid-body dynamics","authors":"Sun-Hyun Youn","doi":"10.1007/s40042-026-01666-w","DOIUrl":"10.1007/s40042-026-01666-w","url":null,"abstract":"<div><p>Most conventional studies on tennis serve biomechanics rely on phenomenological observations comparing professional and amateur players or on AI-driven statistical analyses of motion data. While effective at describing <i>what</i> elite players do, these approaches often fail to explain <i>why</i> such motions are physically necessary from a mechanistic perspective. This paper proposes a deterministic, physics-based approach to the tennis serve using a 12-degree-of-freedom multi-segment model of the human upper body. Rather than fitting the model to motion capture data, we solve the inverse kinematics problem via trajectory optimization to satisfy the aerodynamic boundary conditions required for flat, slice, and kick serves. We subsequently perform an inverse dynamics analysis based on the Principle of Virtual Power to compute the net joint torques. The simulation results reveal that while kinematic trajectories for different serves may share visual similarities, the underlying kinetic profiles differ drastically. A critical finding is that joints exhibiting minimal angular displacement, particularly at the wrist, require substantial and highly time-varying torques to counteract gravitational loading and dynamic coupling effects. By elucidating the dissociation between visible kinematics and internal kinetics, this study provides a first-principles framework for understanding the mechanics of the tennis serve.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"686 - 696"},"PeriodicalIF":1.0,"publicationDate":"2026-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40042-026-01666-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biometric occupancy detection algorithm (BODA): a YOLO-based safety interlock for enhancing radiotherapy room safety","authors":"Yeochan Youn,&nbsp;Gaoyuan Shao,&nbsp;Yelang Lee,&nbsp;Leah Chung,&nbsp;Daegun Kim,&nbsp;Jae-Hong Jung,&nbsp;Youngjin Lee,&nbsp;Kyung-Bae Lee,&nbsp;James J. Sohn","doi":"10.1007/s40042-026-01677-7","DOIUrl":"10.1007/s40042-026-01677-7","url":null,"abstract":"<div><p>This study aims to develop and evaluate the biometric occupancy detection algorithm (BODA), a computer vision-based system designed to detect human presence within a linear accelerator (LINAC) vault and prevent unintended exposure by issuing real-time alerts prior to beam activation. A YOLOv11n object detection model was fine-tuned on a dataset of 14,724 images curated from publicly available online sources to represent realistic clinical scenarios, including ambulatory persons, wheelchairs, and beds. To optimize model performance, three transfer-learning strategies were compared: full model fine-tuning, detection head-only fine-tuning, and low-rank adaptation (LoRA), a parameter-efficient fine-tuning (PEFT) technique. The final model was deployed in an application that monitors room occupancy in real time by analyzing the direction of individuals crossing a reference line within the video frame. The LoRA fine-tuning strategy demonstrated the most clinically favorable performance. This model achieved the highest recall of 0.825 and mAP@50–95 of 0.626, alongside a precision of 0.880 and mAP@50 of 0.920. In a simulated clinical environment, the system demonstrated practical feasibility by accurately detecting human presence, tracking occupancy status, and generating alerts in real-time. This demonstrates the potential for computer vision technology to strengthen the safety culture in radiation oncology.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 7","pages":"792 - 797"},"PeriodicalIF":1.0,"publicationDate":"2026-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149023223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Harmonic-assisted illumination-parameter estimation in binary-harmonic incoherent structured illumination microscopy","authors":"Junehyung Yim,&nbsp;Jongwoo Kim","doi":"10.1007/s40042-026-01665-x","DOIUrl":"10.1007/s40042-026-01665-x","url":null,"abstract":"<div><p>Non-interferometric structured illumination microscopy (SIM) is widely used for super-resolution imaging. However, in digital micromirror device (DMD)-based SIM, the modulation depth often decreases rapidly at high spatial frequencies, which degrades illumination-parameter estimation (wavevectors and phases) and consequently limits reconstruction quality. Here, we propose binary-harmonic incoherent SIM (BH-iSIM), a harmonic-assisted framework for the estimation of illumination parameters and reconstruction of images. BH-iSIM exploits the higher-order components generated by binary DMD patterns by tuning the illumination period so that both the strong first-order component and the weaker third-harmonic component lie within the optical passband. The first-order peak is robustly localized using principal component analysis (PCA), and the third-harmonic location and corresponding illumination parameters are inferred through the harmonic relationship, avoiding direct detection of strongly attenuated high-frequency peaks. BH-iSIM is validated using resolution-target simulations across a range of super-resolution ratios, additional simulations under varying sampling conditions (i.e., pixel size), and an experimental microtubule dataset against a reference reconstruction. BH-iSIM maintains stable wavevector-estimation in high-frequency regimes with peak-localization errors below 0.05 pixels. These results indicate that binary-pattern illumination design combined with harmonic-assisted estimation improves parameter-estimation stability and practical resolution gains in non-interferometric DMD-SIM without additional hardware modifications.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"627 - 638"},"PeriodicalIF":1.0,"publicationDate":"2026-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of MHD boundary layer flow of Maxwell nanofluid over a nonlinear stretching sheet employing the Buongiorno model","authors":"Binaya Kumar Baral,&nbsp;Lokendra Kumar","doi":"10.1007/s40042-026-01662-0","DOIUrl":"10.1007/s40042-026-01662-0","url":null,"abstract":"<div><p>The steady two-dimensional boundary-layer flow, heat transfer, and nanoparticle mass transfer properties of a Maxwell nanofluid across a nonlinearly stretching sheet under the influence of a transverse magnetic field are investigated numerically in this work. The analysis takes into account fluid elasticity, magnetohydrodynamic effects, and transport mechanisms for nanoparticles based on Buongiorno’s nanofluid model, which takes thermophoretic diffusion and Brownian motion into account. A linked system of ordinary differential equations is formed from the governing nonlinear partial differential equations by using appropriate similarity transformations. Combined with the Runge–Kutta–Fehlberg (RK-45) method, the Shooting method is used to solve these equations numerically. The effects on the velocity, temperature, and nanoparticle concentration distributions of the magnetic parameter <i>M</i>, viscoelastic (Maxwell) parameter <i>K</i>, nonlinear stretching parameter <i>n</i>, Prandtl number Pr, Brownian motion parameter <span>(N_textrm{b})</span>, thermophoresis parameter <span>(N_textrm{t})</span>, and Lewis number Le are investigated in a comprehensive parametric study. The momentum boundary layer is found to be dramatically altered by increasing magnetic and elastic effects, but thermophoresis and Brownian motion have competing roles in heat and concentration transport. Mass diffusion is highly regulated by the Prandtl number, and heat diffusion by the Lewis number. Excellent agreement with previously published results is achieved, with the present numerical values matching the existing data up to four decimal places, validating the accuracy and reliability of the proposed shooting approach. The results of this study provide important insight on how to improve mass and heat transport properties in viscoelastic nanofluids. Furthermore, it is expected that the findings will be helpful in the design and optimization of advanced thermal systems with possible uses in energy systems, polymer processing, magnetic materials, improved cooling technologies, and other technical and industrial processes.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"658 - 676"},"PeriodicalIF":1.0,"publicationDate":"2026-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A real-time patient orientation verification system using pose estimation in CT simulation","authors":"Hyunji Amy Kim,&nbsp;Elliott Choi,&nbsp;Estella Choi,&nbsp;Youngjin Lee,&nbsp;Daegun Kim,&nbsp;Jae-Hong Jung,&nbsp;Kyung-Bae Lee,&nbsp;James J. Sohn","doi":"10.1007/s40042-026-01664-y","DOIUrl":"10.1007/s40042-026-01664-y","url":null,"abstract":"<div><p>Patient orientation mis-entry during computed tomography (CT) simulation represents a critical failure mode that corrupts the digital imaging and communications in medicine (DICOM) coordinate system, necessitating patient recall for re-scanning or complex manual corrections. We implemented a tool called just another secondary evaluation (JASE), an automated real-time verification system to prevent these errors. JASE uses a standard webcam to classify patient orientation into four standard categories: head-first-supine (HFS), head-first-prone (HFP), feet-first-supine (FFS), and feet-first-prone (FFP). We compared two approaches: transfer learning with MobileNetV2 and a multilayer perceptron (MLP) using MediaPipe pose landmarks. The system displays real-time orientation on an LCD screen adjacent to the CT console. The MLP model achieved 98.3% accuracy (1/49 misclassifications) versus 96.2% for MobileNetV2 (3/80 misclassifications) on an independent test set. Real-time implementation demonstrated stable performance, which indicates the potential for future clinical deployment pending validation in actual CT simulation workflows. JASE provides a low-cost, effective solution for preventing orientation errors at the point of entry. The system’s applicability extends beyond radiation oncology to radiology and nuclear medicine departments using similar imaging protocols.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"677 - 685"},"PeriodicalIF":1.0,"publicationDate":"2026-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slip-driven thermal transport in axisymmetric pipe flow of Sisko fluid with internal heat generation","authors":"M. Y. Rafiq,&nbsp;Ramy Mahmoud Hafez,&nbsp;Z. Abbas,&nbsp;Kamal Barghout,&nbsp;Nidal Abu-Libdeh","doi":"10.1007/s40042-026-01670-0","DOIUrl":"10.1007/s40042-026-01670-0","url":null,"abstract":"<div><p>This study presents an analytical investigation of steady laminar flow and heat transfer of a non-Newtonian Sisko fluid in a circular pipe, motivated by its important applications in polymer processing, biomedical systems, and thermal engineering. The model incorporates velocity and thermal slip, along with internal heat generation/absorption and viscous dissipation, to represent realistic physical conditions. The governing nonlinear equations are solved using the regular perturbation method, yielding closed-form expressions for velocity and temperature distributions up to first order. The influence of key parameters, including the non-Newtonian parameter, slip coefficients, Brinkman number, and heat generation parameter, is examined. The results show that increasing the non-Newtonian parameter enhances axial velocity and heat transfer. Moreover, higher Brinkman number and heat generation significantly elevate the temperature due to combined viscous and internal heating effects. The obtained results are in good agreement with existing studies, confirming the validity of the analytical approach. These findings provide useful physical insight for the design and optimization of systems involving non-Newtonian fluid flow and heat transfer.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"645 - 657"},"PeriodicalIF":1.0,"publicationDate":"2026-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s40042-026-01670-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pseudorapidity distribution study for shower particles emerged in the interactions of (^{84}{text {Kr}}) with emulsion at 1 GeV per nucleon","authors":"M. K. Singh,&nbsp;M. Sharma","doi":"10.1007/s40042-026-01669-7","DOIUrl":"10.1007/s40042-026-01669-7","url":null,"abstract":"<div><p>An important area of contemporary particle and nuclear physics is investigating the nature of heavy ion reactions at high energies. Pseudorapidity, (<span>(eta )</span>), is a crucial parameter for analyzing the mechanisms of particle production in high-energy collisions between nuclei with nuclear emulsion detector (NED). In this paper <span>(eta )</span> distribution of shower particles produced in the interaction of <span>(^{84}{text {Kr}})</span> with nuclear emulsions at 1 A GeV have been studied using two different parameters <span>(N_textrm{h})</span> (target size) and <i>Q</i> (degree of centrality). The different <span>(eta )</span>-distributions can be described by Gaussian distribution. The statistical moments of the shower particles’ <span>(eta )</span> distribution such as <i>M</i> (mean), <span>(sigma ^{2})</span> (variance), and scaled variance <span>(omega )</span> (<span>(sigma ^{2})</span>/<i>M</i>) are measured. These observations reveal that the width (i.e., dispersion) of these distributions shows only a weak dependence on the type of projectile, while the mean value of <span>(eta )</span> increases with increasing projectile mass (<span>(A_textrm{P})</span>). This study also shows that the cascading effect i.e., the created pions scattering on another target nucleon before emission becomes more pronounced as the target size increases. The <span>(omega )</span> values, which characterize the fluctuations of the distributions, decrease slowly with increasing <span>(N_textrm{h})</span> values.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"608 - 613"},"PeriodicalIF":1.0,"publicationDate":"2026-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum Monte Carlo calculation of critical temperature of flat-band superconductivity in the Lieb-lattice Hubbard model","authors":"Jicheol Kim,&nbsp;Dong-Hee Kim","doi":"10.1007/s40042-026-01663-z","DOIUrl":"10.1007/s40042-026-01663-z","url":null,"abstract":"<div><p>We investigate a superconducting transition in the attractive Hubbard model on the Lieb lattice at the half-filled flat band with linear band-touching. Using the determinant quantum Monte Carlo simulations, we estimate the Berezinskii–Kosterlitz–Thouless (BKT) transition temperature for the onsite interaction <span>(|U|=1)</span> based on the universal relation with the superfluid weight. We also perform a finite-size scaling analysis of the pair-field structure factor, examining its consistency with the BKT transition. Our estimate of the transition temperature <span>(T_c approx 0.032)</span> exhibits notable differences from previous static and dynamical mean-field estimates, implying a significant role of quantum fluctuations near the onset of superconductivity in this gapless flat-band system.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"639 - 644"},"PeriodicalIF":1.0,"publicationDate":"2026-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probe absorption properties and Kerr effect of a nanomechanical resonator system with a flux qubit","authors":"Jin-sheng Chen,&nbsp;Qing-hong Liao,&nbsp;Jian-gong Hu,&nbsp;Jin-hua Zhang","doi":"10.1007/s40042-026-01658-w","DOIUrl":"10.1007/s40042-026-01658-w","url":null,"abstract":"<div><p>This work demonstrates the probe absorption and nonlinear optical response in a coupled electromechanical system. The system integrates a superconducting flux qubit directly coupled to two nanomechanical resonators, which are themselves coupled to a third resonator, forming a closed-loop network. In this system, the transparency based on mechanically induced coherent population oscillations can be controlled by tuning the Rabi frequency and damping rate of the mechanical resonators. This control enables reconfiguration of the absorption spectrum from a single peak to multiple asymmetric resonances. Spectral shifts and broadening are further induced by selective detuning and collective decay, while enhanced nonlinear sidebands are generated by optical pumping. These effects are explained by quantum interference and mode hybridization. The results provide a theoretical reference for tunable spectral engineering in hybrid electromechanical systems.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"614 - 626"},"PeriodicalIF":1.0,"publicationDate":"2026-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-commutative geometry for D-branes in large R–R field background","authors":"Chen-Te Ma","doi":"10.1007/s40042-026-01657-x","DOIUrl":"10.1007/s40042-026-01657-x","url":null,"abstract":"<div><p>We examine the role of non-commutative geometry in D<i>p</i>-branes within large R–R field backgrounds. In this context, the background of a significant (<span>(p-1)</span>)-form R–R field can be effectively described using a (<span>(p-1)</span>)-bracket, similar to the method used in the NS–NS case. We begin by recalling how non-commutative geometry arises from the quantization of open string theory. In this framework, the Seiberg–Witten map is a key element that establishes the equivalence between commutative and non-commutative descriptions in the low-energy effective theory. The Poisson bracket characterizes non-commutative structures, with deformation achieved through the Moyal product. Next, we show how the Nambu–Poisson bracket emerges in the context of a single D4-brane with the large R–R field background limit, starting from the BLG model. The generalization to a D<i>p</i>-brane leads to the (<span>(p-1)</span>)-bracket description, which reveals a duality web relating NS–NS and R–R field backgrounds via T-duality and S-duality in the low-energy limit. Finally, we extend the single D-brane construction to multiple D-branes by promoting the ordinary product in the bracket to a covariant derivative at the Poisson level.</p></div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"89 6","pages":"551 - 589"},"PeriodicalIF":1.0,"publicationDate":"2026-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148909687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}