43,637 results on '"Lee, Chang"'
Search Results
2. Direct observational evidence of multi-epoch massive star formation in G24.47+0.49
- Author
-
Saha, Anindya, Tej, Anandmayee, Liu, Hong-Li, Liu, Tie, Garay, Guido, Goldsmith, Paul F., Lee, Chang Won, He, Jinhua, Juvela, Mika, Bronfman, Leonardo, Baug, Tapas, Vazquez-Semadeni, Enrique, Sanhueza, Patricio, Li, Shanghuo, Chibueze, James O., Bhadari, N. K., Dewangan, Lokesh K., Das, Swagat Ranjan, Xu, Feng-Wei, Issac, Namitha, Hwang, Jihye, and Toth, L. Viktor
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Using new continuum and molecular line data from the ALMA Three-millimeter Observations of Massive Star-forming Regions (ATOMS) survey and archival VLA, 4.86 GHz data, we present direct observational evidence of hierarchical triggering relating three epochs of massive star formation in a ring-like H II region, G24.47+0.49. We find from radio flux analysis that it is excited by a massive star(s) of spectral type O8.5V-O8V from the first epoch of star formation. The swept-up ionized ring structure shows evidence of secondary collapse, and within this ring a burst of massive star formation is observed in different evolutionary phases, which constitutes the second epoch. ATOMS spectral line (e.g., HCO$^+$(1-0)) observations reveal an outer concentric molecular gas ring expanding at a velocity of $\sim$ 9 $\rm km\,s^{-1}$, constituting the direct and unambiguous detection of an expanding molecular ring. It harbors twelve dense molecular cores with surface mass density greater than 0.05 $\rm g\,cm^{-2}$, a threshold typical of massive star formation. Half of them are found to be subvirial, and thus in gravitational collapse, making them third epoch of potential massive star-forming sites., Comment: 18 pages, 7 figures, accepted for publication in The Astrophysical Journal Letters
- Published
- 2024
3. A Nonoverlapping Domain Decomposition Method for Extreme Learning Machines: Elliptic Problems
- Author
-
Lee, Chang-Ock, Lee, Youngkyu, and Ryoo, Byungeun
- Subjects
Mathematics - Numerical Analysis ,Computer Science - Computational Engineering, Finance, and Science ,Computer Science - Machine Learning ,65N55 (Primary), 35J25, 68T07 (Secondary) - Abstract
Extreme learning machine (ELM) is a methodology for solving partial differential equations (PDEs) using a single hidden layer feed-forward neural network. It presets the weight/bias coefficients in the hidden layer with random values, which remain fixed throughout the computation, and uses a linear least squares method for training the parameters of the output layer of the neural network. It is known to be much faster than Physics informed neural networks. However, classical ELM is still computationally expensive when a high level of representation is desired in the solution as this requires solving a large least squares system. In this paper, we propose a nonoverlapping domain decomposition method (DDM) for ELMs that not only reduces the training time of ELMs, but is also suitable for parallel computation. In numerical analysis, DDMs have been widely studied to reduce the time to obtain finite element solutions for elliptic PDEs through parallel computation. Among these approaches, nonoverlapping DDMs are attracting the most attention. Motivated by these methods, we introduce local neural networks, which are valid only at corresponding subdomains, and an auxiliary variable at the interface. We construct a system on the variable and the parameters of local neural networks. A Schur complement system on the interface can be derived by eliminating the parameters of the output layer. The auxiliary variable is then directly obtained by solving the reduced system after which the parameters for each local neural network are solved in parallel. A method for initializing the hidden layer parameters suitable for high approximation quality in large systems is also proposed. Numerical results that verify the acceleration performance of the proposed method with respect to the number of subdomains are presented., Comment: 18 pages, 4 figures, 7 tables
- Published
- 2024
4. Topological Materials for Near-Field Radiative Heat Transfer
- Author
-
Didari-Bader, Azadeh, Kim, Seonyeong, Choi, Heejin, Seo, Sunae, Biswas, Piyali, Jeong, Heejeong, and Lee, Chang-Won
- Subjects
Physics - Optics ,Quantum Physics - Abstract
Topological materials provide a platform that utilizes the geometric characteristics of structured materials to control the flow of waves, enabling unidirectional and protected transmission that is immune to defects or impurities. The topologically designed photonic materials can carry quantum states and electromagnetic energy, benefiting nanolasers or quantum photonic systems. This article reviews recent advances in the topological applications of photonic materials for radiative heat transfer, especially in the near field. When the separation distance between media is considerably smaller than the thermal wavelength, the heat transfer exhibits super-Planckian behavior that surpasses Planck's blackbody predictions. Near-field thermal radiation in subwavelength systems supporting surface modes has various applications, including nanoscale thermal management and energy conversion. Photonic materials and structures that support topological surface states show immense potential for enhancing or suppressing near-field thermal radiation. We present various topological effects, such as periodic and quasi-periodic nanoparticle arrays, Dirac and Weyl semimetal-based materials, structures with broken global symmetries, and other topological insulators, on near-field heat transfer. Also, the possibility of realizing near-field thermal radiation in such topological materials for alternative thermal management and heat flux guiding in nano-scale systems is discussed based on the existing technology.
- Published
- 2024
- Full Text
- View/download PDF
5. The Formation of Filaments and Dense cores in the Cocoon Nebula (IC~5146)
- Author
-
Chung, Eun Jung, Lee, Chang Won, Kim, Shinyoung, Tafalla, Mario, Yoo, Hyunju, Cho, Jungyeon, and Kwon, Woojin
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
We present 850~$\mu$m linear polarization and C$^{18}$O~(3-2) and $^{13}$CO~(3-2) molecular line observations toward the filaments (F13 and F13S) in the Cocoon Nebula (IC~5146) using the JCMT POL-2 and HARP instruments. F13 and F13S are found to be thermally supercritical with identified dense cores along their crests. Our findings include that the polarization fraction decreases in denser regions, indicating reduced dust grain alignment efficiency. The magnetic field vectors at core scales tend to be parallel to the filaments, but disturbed at the high density regions. Magnetic field strengths measured using the Davis-Chandrasekhar-Fermi method are 58$\pm$31 and 40$\pm$9~$\mu$G for F13 and F13S, respectively, and it reveals subcritical and sub-Alfv\'enic filaments, emphasizing the importance of magnetic fields in the Cocoon region. Sinusoidal C$^{18}$O~(3-2) velocity and density distributions are observed along the filaments' skeletons, and their variations are mostly displaced by $\sim1/4 \times$wavelength of the sinusoid, indicating core formation occurred through the fragmentation of a gravitationally unstable filament, but with shorter core spacings than predicted. Large scale velocity fields of F13 and F13S, studied using $^{13}$CO~(3-2) data, present V-shape transverse velocity structure. We propose a scenario for the formation and evolution of F13 and F13S, along with the dense cores within them. A radiation shock front generated by a B-type star collided with a sheet-like cloud about 1.4~Myr ago, the filaments became thermally critical due to mass infall through self-gravity $\sim$1~Myr ago, and subsequently dense cores formed through gravitational fragmentation, accompanied by the disturbance of the magnetic field., Comment: 26 pages, 19 figures, 3 tables, Accepted for publication in ApJ
- Published
- 2024
- Full Text
- View/download PDF
6. Exploring Baryon Resonances with Transition Generalized Parton Distributions: Status and Perspectives
- Author
-
Diehl, Stefan, Joo, Kyungseon, Semenov-Tian-Shansky, Kirill, Weiss, Christian, Braun, Vladimir, Chang, Wen-Chen, Chatagnon, Pierre, Constantinou, Martha, Guo, Yuxun, Hutauruk, Parada T. P., Jo, Hyon-Suk, Kim, Andrey, Kim, Jun-Young, Kroll, Peter, Kumano, Shunzo, Lee, Chang-Hwan, Liuti, Simonetta, McNulty, Ronan, Son, Hyeon-Dong, Sznajder, Pawel, Usman, Ali, Van Hulse, Charlotte, Vanderhaeghen, Marc, and Winn, Michael
- Subjects
High Energy Physics - Phenomenology ,High Energy Physics - Experiment ,Nuclear Theory - Abstract
QCD gives rise to a rich spectrum of excited baryon states. Understanding their internal structure is important for many areas of nuclear physics, such as nuclear forces, dense matter, and neutrino-nucleus interactions. Generalized parton distributions (GPDs) are an established tool for characterizing the QCD structure of the ground-state nucleon. They are used to create 3D tomographic images of the quark/gluon structure and quantify the mechanical properties such as the distribution of mass, angular momentum and forces in the system. Transition GPDs extend these concepts to $N \rightarrow N^\ast$ transitions and can be used to characterize the 3D structure and mechanical properties of baryon resonances. They can be probed in high-momentum-transfer exclusive electroproduction processes with resonance transitions $e + N \rightarrow e' + M + N^\ast$, such as deeply-virtual Compton scattering ($M = \gamma$) or meson production ($M = \pi, K$, $etc.$), and in related photon/hadron-induced processes. This White Paper describes a research program aiming to explore baryon resonance structure with transition GPDs. This includes the properties and interpretation of the transition GPDs, theoretical methods for structures and processes, first experimental results from JLab 12 GeV, future measurements with existing and planned facilities (JLab detector and energy upgrades, COMPASS/AMBER, EIC, EicC, J-PARC, LHC ultraperihperal collisions), and the theoretical and experimental developments needed to realize this program.
- Published
- 2024
7. Early Planet Formation in Embedded Disks (eDisk) XV: Influence of Magnetic Field Morphology in Dense Cores on Sizes of Protostellar Disks
- Author
-
Yen, Hsi-Wei, Williams, Jonathan P., Sai, Jinshi, Koch, Patrick M., Han, Ilseung, Jørgensen, Jes K., Kwon, Woojin, Lee, Chang Won, Li, Zhi-Yun, Looney, Leslie W., Narang, Mayank, Ohashi, Nagayoshi, Takakuwa, Shigehisa, Tobin, John J., de Gregorio-Monsalvo, Itziar, Lai, Shih-Ping, Lee, Jeong-Eun, and Tomida, Kengo
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
The magnetic field of a molecular cloud core may play a role in the formation of circumstellar disks in the core. We present magnetic field morphologies in protostellar cores of 16 targets in the Atacama Large Millimeter/submillimeter Array large program "Early Planet Formation in Embedded Disks (eDisk)", which resolved their disks with 7 au resolutions. The 0.1-pc scale magnetic field morphologies were inferred from the James Clerk Maxwell Telescope (JCMT) POL-2 observations. The mean orientations and angular dispersions of the magnetic fields in the dense cores are measured and compared with the radii of the 1.3 mm continuum disks and the dynamically determined protostellar masses from the eDisk program. We observe a significant correlation between the disk radii and the stellar masses. We do not find any statistically significant dependence of the disk radii on the projected misalignment angles between the rotational axes of the disks and the magnetic fields in the dense cores, nor on the angular dispersions of the magnetic fields within these cores. However, when considering the projection effect, we cannot rule out a positive correlation between disk radii and misalignment angles in three-dimensional space. Our results suggest that the morphologies of magnetic fields in dense cores do not play a dominant role in the disk formation process. Instead, the sizes of protostellar disks may be more strongly affected by the amount of mass that has been accreted onto star+disk systems, and possibly other parameters, for example, magnetic field strength, core rotation, and magnetic diffusivity., Comment: 14 pages, 4 figures, accepted by ApJ
- Published
- 2024
8. Model Predictive Guidance for Fuel-Optimal Landing of Reusable Launch Vehicles
- Author
-
Jung, Ki-Wook, Lee, Sang-Don, Jung, Cheol-Goo, and Lee, Chang-Hun
- Subjects
Electrical Engineering and Systems Science - Systems and Control - Abstract
This paper introduces a landing guidance strategy for reusable launch vehicles (RLVs) using a model predictive approach based on sequential convex programming (SCP). The proposed approach devises two distinct optimal control problems (OCPs): planning a fuel-optimal landing trajectory that accommodates practical path constraints specific to RLVs, and determining real-time optimal tracking commands. This dual optimization strategy allows for reduced computational load through adjustable prediction horizon lengths in the tracking task, achieving near closed-loop performance. Enhancements in model fidelity for the tracking task are achieved through an alternative rotational dynamics representation, enabling a more stable numerical solution of the OCP and accounting for vehicle transient dynamics. Furthermore, modifications of aerodynamic force in both planning and tracking phases are proposed, tailored for thrust-vector-controlled RLVs, to reduce the fidelity gap without adding computational complexity. Extensive 6-DOF simulation experiments validate the effectiveness and improved guidance performance of the proposed algorithm.
- Published
- 2024
9. The ALMA-QUARKS Survey: II. the ACA 1.3 mm continuum source catalog and the assembly of dense gas in massive star-forming clumps
- Author
-
Xu, Fengwei, Wang, Ke, Liu, Tie, Zhu, Lei, Garay, Guido, Liu, Xunchuan, Goldsmith, Paul, Zhang, Qizhou, Sanhueza, Patricio, Qin, Shengli, He, Jinhua, Juvela, Mika, Tej, Anandmayee, Liu, Hongli, Li, Shanghuo, Morii, Kaho, Zhang, Siju, Zhou, Jianwen, Stutz, Amelia, Evans, Neal J., Kee-Tae, Kim, Liu, Shengyuan, Mardones, Diego, Li, Guangxing, Bronfman, Leonardo, Tatematsu, Ken'ichi, Lee, Chang Won, Lu, Xing, Mai, Xiaofeng, Jiao, Sihan, Chibueze, James O., Su, Keyun, and Toth, L. Viktor
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Leveraging the high resolution, high sensitivity, and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array (ALMA), the QUARKS survey, standing for "Querying Underlying mechanisms of massive star formation with ALMA-Resolved gas Kinematics and Structures", is observing 139 massive star-forming clumps at ALMA Band 6 ($\lambda\sim$ 1.3 mm). This paper introduces the Atacama Compact Array (ACA) 7-m data. Combining multi-wavelength data, we provide the first edition of QUARKS atlas, offering insights into the multiscale and multiphase interstellar medium in high-mass star formation. The ACA 1.3 mm catalog includes 207 continuum sources that are called ACA sources. Their gas kinetic temperatures are estimated using three formaldehyde (H$_2$CO) transitions with a non-LTE radiation transfer model, and the mass and density are derived from a dust emission model. The ACA sources are massive (16-84 percentile values of 6-160 $M_{\odot}$), gravity-dominated ($M\propto R^{1.1}$) fragments within massive clumps, with supersonic turbulence ($\mathcal{M}>1$) and embedded star-forming protoclusters. We find a linear correlation between the masses of the fragments and the massive clumps, with a ratio of 6% between the two. When considering the fragments as representative of dense gas, the ratio indicates a dense gas fraction (DGF) of 6%, although with a wide scatter ranging from 1% to 10%. If we consider the QUARKS massive clumps to be what is observed at various scales, then the size-independent DGF indicates a self-similar fragmentation or collapsing mode in protocluster formation. With the ACA data over four orders of magnitude of luminosity-to-mass ratio ($L/M$), we find that the DGF increases significantly with $L/M$, which indicates clump evolutionary stage. We observed a limited fragmentation at the subclump scale, which can be explained by dynamic global collapse process., Comment: 24 pages, 7 figures. Accepted for publication in Research in Astronomy and Astrophysics. QUARKS atlas link: https://drive.google.com/file/d/1KTqXxCDduYepvLd9kIvZVSSytK48OmfL/view?usp=sharing
- Published
- 2024
10. Efficient, indistinguishable telecom C-band photons using a tapered nanobeam
- Author
-
Rahaman, Mohammad Habibur, Harper, Samuel, Lee, Chang-Min, Kim, Kyu-Young, Buyukkaya, Mustafa Atabey, Patel, Victor J., Hawkins, Samuel D., Kim, Je-Hyung, Addamane, Sadhvikas, and Waks, Edo
- Subjects
Quantum Physics - Abstract
Telecom C-band single photons exhibit the lowest attenuation in optical fibers, enabling long-haul quantum-secured communication. However, efficient coupling with optical fibers is crucial for these single photons to be effective carriers in long-distance transmission. In this work, we demonstrate an efficient fiber-coupled single photon source at the telecom C-band using InAs/InP quantum dots coupled to a tapered nanobeam. The tapered nanobeam structure facilitates directional emission that is mode-matched to a lensed fiber, resulting in a collection efficiency of up to 65% from the nanobeam to a single-mode fiber. Using this approach, we demonstrate single photon count rates of 575 $\pm$ 5 Kcps and a single photon purity of $g^2$ (0) = 0.015 $\pm$ 0.003. Additionally, we demonstrate Hong-Ou Mandel interference from the emitted photons with a visibility of 0.84 $\pm$ 0.06. From these measurements, we determine a photon coherence time of 450 $\pm$ 20 ps, a factor of just 8.3 away from the lifetime limit. This work represents an important step towards the development of telecom C-band single-photon sources emitting bright, pure, and indistinguishable photons, which are necessary to realize fiber-based long-distance quantum networks
- Published
- 2024
11. Connections between Reachability and Time Optimality
- Author
-
Bae, Juho, Bai, Ji Hoon, Lee, Byung-Yoon, Lee, Jun-Yong, and Lee, Chang-Hun
- Subjects
Mathematics - Optimization and Control ,Electrical Engineering and Systems Science - Systems and Control - Abstract
This paper presents the concept of an equivalence relation between the set of optimal control problems. By leveraging this concept, we show that the boundary of the reachability set can be constructed by the solutions of time optimal problems. Alongside, a more generalized equivalence theorem is presented together. The findings facilitate the use of solution structures from a certain class of optimal control problems to address problems in corresponding equivalent classes. As a byproduct, we state and prove the construction methods of the reachability sets of three-dimensional curves with prescribed curvature bound. The findings are twofold: Firstly, we prove that any boundary point of the reachability set, with the terminal direction taken into account, can be accessed via curves of H, CSC, CCC, or their respective subsegments, where H denotes a helicoidal arc, C a circular arc with maximum curvature, and S a straight segment. Secondly, we show that any boundary point of the reachability set, without considering the terminal direction, can be accessed by curves of CC, CS, or their respective subsegments. These findings extend the developments presented in literature regarding planar curves, or Dubins car dynamics, into spatial curves in $\mathbb{R}^3$. For higher dimensions, we confirm that the problem of identifying the reachability set of curvature bounded paths subsumes the well-known Markov-Dubins problem. These advancements in understanding the reachability of curvature bounded paths in $\mathbb{R}^3$ hold significant practical implications, particularly in the contexts of mission planning problems and time optimal guidance., Comment: Submitted to Automatica
- Published
- 2024
12. Early Planet Formation in Embedded Disks (eDisk) XIII: Aligned Disks with Non-Settled Dust Around the Newly Resolved Class 0 Protobinary R CrA IRAS 32
- Author
-
Encalada, Frankie J., Looney, Leslie W., Takakuwa, Shigehisa, Tobin, John J., Ohashi, Nagayoshi, Jørgensen, Jes K., Li, Zhi-Yun, Aikawa, Yuri, Aso, Yusuke, Koch, Patrick M., Kwon, Woojin, Lai, Shih-Ping, Lee, Chang Won, Lin, Zhe-Yu Daniel, Santamarıa-Miranda, Alejandro, de Gregorio-Monsalvo, Itziar, Phuong, Nguyen Thi, Plunkett, Adele, Sai, Jinshi, Sharma, Rajeeb, Yen, Hsi-Wei, and Han, Ilseung
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
Young protostellar binary systems, with expected ages less than $\sim$10$^5$ years, are little modified since birth, providing key clues to binary formation and evolution. We present a first look at the young, Class 0 binary protostellar system R CrA IRAS 32 from the Early Planet Formation in Embedded Disks (eDisk) ALMA large program, which observed the system in the 1.3 mm continuum emission, $^{12}$CO (2-1), $^{13}$CO (2-1), C$^{18}$O (2-1), SO (6$_5$-5$_4$), and nine other molecular lines that trace disk, envelope, shocks, and outflows. With a continuum resolution of $\sim$0.03$^{\prime\prime}$ ($\sim$5 au, at a distance of 150 pc), we characterize the newly discovered binary system with a separation of 207 au, their circumstellar disks, and a circumbinary disk-like structure. The circumstellar disk radii are 26.9$\pm$0.3 and 22.8$\pm$0.3 au for sources A and B, respectively, and their circumstellar disk dust masses are estimated as 22.5$\pm$1.1 and 12.4$\pm$0.6 M$_{\Earth}$. The circumstellar disks and the circumbinary structure have well aligned position angles and inclinations, indicating formation in a smooth, ordered process such as disk fragmentation. In addition, the circumstellar disks have a near/far-side asymmetry in the continuum emission suggesting that the dust has yet to settle into a thin layer near the midplane. Spectral analysis of CO isotopologues reveals outflows that originate from both of the sources and possibly from the circumbinary disk-like structure. Furthermore, we detect Keplerian rotation in the $^{13}$CO isotopologues toward both circumstellar disks and likely Keplerian rotation in the circumbinary structure; the latter suggests that it is probably a circumbinary disk., Comment: 33 pages, 29 figures, 6 tables
- Published
- 2024
13. $Herschel$ investigation of cores and filamentary structures in L1251 located in the Cepheus flare
- Author
-
Dewan, Divyansh, Soam, Archana, Zhang, Guo-Yin, Lasrado, Akhil, Singh, Saikhom Pravash, and Lee, Chang Won
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
Context: Molecular clouds are the prime locations of star formation. These clouds contain filamentary structures and cores which are crucial in the formation of young stars. Aims: In this work, we aim to quantify the physical properties of structural characteristics within the molecular cloud L1251 to better understand the initial conditions for star formation. Methods: We applied the getsf algorithm to identify cores and filaments within the molecular cloud L1251 using the Herschel multiband dust continuum image, enabling us to measure their respective physical properties. Additionally, we utilized an enhanced differential term algorithm to produce high-resolution temperature maps and column density maps with a resolution of ${13.5}''$. Results: We identified 122 cores in the region. Out of them, 23 are protostellar cores, 13 are robust prestellar cores, 32 are candidate prestellar cores (including 13 robust prestellar cores and 19 strictly candidate prestellar cores), and 67 are unbound starless cores. getsf also found 147 filament structures in the region. Statistical analysis of the physical properties (mass (M), temperature (T), size, and core brightness (hereafter, we are using the word luminosity (L)) for the core brightness) of obtained cores shows a negative correlation between core mass and temperature and a positive correlation between (M/L) and (M/T). Analysis of the filaments gives a median width of 0.14 pc and no correlation between width and length. Out of those 122 cores, 92 are present in filaments (75.4%) and the remaining were outside them. Out of the cores present in filaments, 57 (62%) cores are present in supercritical filaments ($M_{\rm line}>16M_{\odot }/{\rm pc}$)., Comment: 15 pages, 20 figures, 2 tables, accepted for publication in JAA
- Published
- 2024
14. UncertaintyTrack: Exploiting Detection and Localization Uncertainty in Multi-Object Tracking
- Author
-
Lee, Chang Won and Waslander, Steven L.
- Subjects
Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Robotics - Abstract
Multi-object tracking (MOT) methods have seen a significant boost in performance recently, due to strong interest from the research community and steadily improving object detection methods. The majority of tracking methods follow the tracking-by-detection (TBD) paradigm, blindly trust the incoming detections with no sense of their associated localization uncertainty. This lack of uncertainty awareness poses a problem in safety-critical tasks such as autonomous driving where passengers could be put at risk due to erroneous detections that have propagated to downstream tasks, including MOT. While there are existing works in probabilistic object detection that predict the localization uncertainty around the boxes, no work in 2D MOT for autonomous driving has studied whether these estimates are meaningful enough to be leveraged effectively in object tracking. We introduce UncertaintyTrack, a collection of extensions that can be applied to multiple TBD trackers to account for localization uncertainty estimates from probabilistic object detectors. Experiments on the Berkeley Deep Drive MOT dataset show that the combination of our method and informative uncertainty estimates reduces the number of ID switches by around 19\% and improves mMOTA by 2-3%. The source code is available at https://github.com/TRAILab/UncertaintyTrack, Comment: Accepted to ICRA 2024
- Published
- 2024
15. Nuclear mass table in deformed relativistic Hartree-Bogoliubov theory in continuum, II: Even-$Z$ nuclei
- Author
-
DRHBc Mass Table Collaboration, Guo, Peng, Cao, Xiaojie, Chen, Kangmin, Chen, Zhihui, Cheoun, Myung-Ki, Choi, Yong-Beom, Lam, Pak Chung, Deng, Wenmin, Dong, Jianmin, Du, Pengxiang, Du, Xiaokai, Duan, Kangda, Fan, Xiaohua, Gao, Wei, Geng, Lisheng, Ha, Eunja, He, Xiao-Tao, Hu, Jinniu, Huang, Jingke, Huang, Kun, Huang, Yanan, Huang, Zidan, Da Hyung, Kim, Chan, Hoi Yat, Jiang, Xiaofei, Kim, Seonghyun, Kim, Youngman, Lee, Chang-Hwan, Lee, Jenny, Li, Jian, Li, Minglong, Li, Zhipan, Li, Zhengzheng, Lian, Zhanjiang, Liang, Haozhao, Liu, Lang, Lu, Xiao, Liu, Zhi-Rui, Meng, Jie, Meng, Ziyan, Mun, Myeong-Hwan, Niu, Yifei, Niu, Zhongming, Pan, Cong, Peng, Jing, Qu, Xiaoying, Papakonstantinou, Panagiota, Shang, Tianshuai, Shang, Xinle, Shen, Caiwan, Shen, Guofang, Sun, Tingting, Sun, Xiang-Xiang, Wang, Sibo, Wang, Tianyu, Wang, Yiran, Wang, Yuanyuan, Wu, Jiawei, Wu, Liang, Wu, Xinhui, Xia, Xuewei, Xie, Huihui, Yao, Jiangming, Ip, Ip Kwan Yau, Yiu, To Chung, Yu, Jianghan, Yu, Yangyang, Zhang, Kaiyuan, Zhang, Shijie, Zhang, Shuangquan, Zhang, Wei, Zhang, Xiaoyan, Zhang, Yanxin, Zhang, Ying, Zhang, Yingxun, Zhang, Zhenhua, Zhao, Qiang, Zhao, Yingchun, Zheng, Ruyou, Zhou, Chang, Zhou, Shan-Gui, and Zou, Lianjian
- Subjects
Nuclear Theory ,Astrophysics - Solar and Stellar Astrophysics ,Nuclear Experiment - Abstract
The mass table in the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) with the PC-PK1 density functional has been established for even-$Z$ nuclei with $8\le Z\le120$, extended from the previous work for even-even nuclei [Zhang $\it{et.~al.}$ (DRHBc Mass Table Collaboration), At. Data Nucl. Data Tables 144, 101488 (2022)]. The calculated binding energies, two-nucleon and one-neutron separation energies, root-mean-square (rms) radii of neutron, proton, matter, and charge distributions, quadrupole deformations, and neutron and proton Fermi surfaces are tabulated and compared with available experimental data. A total of 4829 even-$Z$ nuclei are predicted to be bound, with an rms deviation of 1.477 MeV from the 1244 mass data. Good agreement with the available experimental odd-even mass differences, $\alpha$ decay energies, and charge radii is also achieved. The description accuracy for nuclear masses and nucleon separation energies as well as the prediction for drip lines is compared with the results obtained from other relativistic and nonrelativistic density functional. The comparison shows that the DRHBc theory with PC-PK1 provides an excellent microscopic description for the masses of even-$Z$ nuclei. The systematics of the nucleon separation energies, odd-even mass differences, pairing energies, two-nucleon gaps, $\alpha$ decay energies, rms radii, quadrupole deformations, potential energy curves, neutron density distributions, and neutron mean-field potentials are discussed., Comment: 394 pages, 17 figures, 2 tables, published in Atomic Data and Nuclear Data Tables, data file in the TXT form is available for download under "Ancillary files"
- Published
- 2024
- Full Text
- View/download PDF
16. The Effect of State Anxiety and Self-Confidence on Olympic Performance in Korean Athletes
- Author
-
Kim, Taegyu, Lee, Chang-Hyung, Hong, Soung Kyun, and Choi, Young A
- Published
- 2019
- Full Text
- View/download PDF
17. The Effect of Quality of Life and Hope on the Suicide Ideation of the Elderly: The Moderated Mediation Effect of Participation in Lifelong Education
- Author
-
Lee, Chang-Seek, Ryu, Eun-Kyung, and Choi, Yang-Jin
- Published
- 2019
- Full Text
- View/download PDF
18. The influence of marital relations on the happiness of children: Dual mediation effect of the hope and growth mindset
- Author
-
Lee, Chang Seek and Shin, Eun Mi
- Published
- 2018
- Full Text
- View/download PDF
19. Double mediating effects of growth mindset and hope between tourism experience and psychological Well-Being
- Author
-
Lee, Chang Seek, Park, Soo Hyun, and Jang, Ha Young
- Published
- 2018
- Full Text
- View/download PDF
20. The effects of workers'authentic leadership on job stress: Mediating effect of organizational communication and psychological capital
- Author
-
Lee, Gwang Ho and Lee, Chang Seek
- Published
- 2018
- Full Text
- View/download PDF
21. A double mediation of hope and job satisfaction between job stress and turnover intention
- Author
-
Lee, Chang Seek and Jang, Ha Young
- Published
- 2018
- Full Text
- View/download PDF
22. Human rights victimization and Self-Esteem of university students: Mediating effect of hope and moderating effects of human rights awareness
- Author
-
Lee, Chang seek and Ligaya, Massuline Antonio D
- Published
- 2018
- Full Text
- View/download PDF
23. Variables influencing participation in a collective physical activity among employees
- Author
-
Lee, Chang seek, Choi, Yeon Sook, and Jang, Ha Young
- Published
- 2018
- Full Text
- View/download PDF
24. Influence bicycle saddle height on body posture and muslce activity
- Author
-
Kim, Gyeong-Bae, Lee, Chang-Kwon, Lee, Dong-Yeop, Hong, Ji-Heon, Kim, Jin-Seop, and Yu, Jae-Ho
- Published
- 2018
- Full Text
- View/download PDF
25. The effect of participation in exercise therapy on the life satisfaction of parents
- Author
-
Lee, Chang-Hee and Youn, So-Ra
- Published
- 2018
- Full Text
- View/download PDF
26. Factors that affect adolescents' school adaptation
- Author
-
Lee, Chang Seek, Shin, Mi Hee, Koh, Jong Min, Ahn, Hyo Kwon, Kim, Kyung Suk, and Jang, Ha Young
- Published
- 2018
- Full Text
- View/download PDF
27. A research on how sales representative competency affects brand image and the customer loyalty in B2B environment
- Author
-
Seo, Joon-Hyuk, You, Yen-Yoo, Lee, Chang-Won, and Hong, Jung-Wan
- Published
- 2018
- Full Text
- View/download PDF
28. Variables related to the presence or absence of school violence victimization among adolescents
- Author
-
Lee, Chang Seek, Shin, Hye Young, Choi, Youn Sook, and Jang, Ha Young
- Published
- 2018
- Full Text
- View/download PDF
29. Moderating effect of growth mindset between victimization by school violence and school class adjustment
- Author
-
Lee, Chang Seek and Jang, Ha Young
- Published
- 2018
- Full Text
- View/download PDF
30. Mediating effects of hope and organizational effectiveness between authentic leadership and turnover intention
- Author
-
Lee, Chang Seek and Jang, Ha Young
- Published
- 2018
- Full Text
- View/download PDF
31. Using Social Media as e-Portfolios to Support Learning in Higher Education: A Literature Analysis
- Author
-
Siew Lee Chang and Muhammad Kamarul Kabilan
- Abstract
Although e-Portfolio is acknowledged as one of the powerful pedagogical practices that enhance learning in higher education (HE), not much is known about the types of social media (SM) utilized as e-Portfolios and the benefits for students. This literature analysis, using directed content analysis, aims to explore the above vacuum. The research questions in this study are: (1) In what ways do the SM as e-Portfolios benefit students in HE?, (2) To what extent are the benefits of SM as e-Portfolios comparable to those of conventional e-Portfolios? ,and (3) What are the drawbacks that practitioners and researchers need to be concerned with? Findings indicate that blogs are the most popular SM used as e-Portfolios to support learning, followed by social networking sites and collaborative projects. The study yields 13 advantages and 12 drawbacks when SM is manipulated as e-Portfolios. These findings conclude that the use of SM as e-Portfolios has a great potential in supporting students' learning and development by providing an environment for them to learn meaningfully from their experiences and engage in critical reflections and dialogues that allow them to gain new knowledge and valuable insights and thus, improve their skills. A pedagogical framework for the planning and implementation of SM as e-Portfolios is suggested based on the findings and aims of the papers that were reviewed.
- Published
- 2024
- Full Text
- View/download PDF
32. On the Scarcity of Dense Cores ($n>10^{5}$ cm$^{-3}$) in High Latitude Planck Galactic Cold Clumps
- Author
-
Xu, Fengwei, Wang, Ke, Liu, Tie, Eden, David, Liu, Xunchuan, Juvela, Mika, He, Jinhua, Johnstone, Doug, Goldsmith, Paul, Garay, Guido, Wu, Yuefang, Soam, Archana, Traficante, Alessio, Ristorcelli, Isabelle, Falgarone, Edith, Chen, Huei-Ru Vivien, Hirano, Naomi, Doi, Yasuo, Kwon, Woojin, White, Glenn J., Whitworth, Anthony, Sanhueza, Patricio, Rawlings, Mark G., Alina, Dana, Ren, Zhiyuan, Lee, Chang Won, Tatematsu, Ken'ichi, Zhang, Chuan-Peng, Zhou, Jianjun, Lai, Shih-Ping, Ward-Thompson, Derek, Liu, Sheng-Yuan, Gu, Qilao, Chakali, Eswaraiah, Zhu, Lei, Mardones, Diego, and Tóth, L. Viktor
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
High-latitude ($|b|>30^{\circ}$) molecular clouds have virial parameters that exceed 1, but whether these clouds can form stars has not been studied systematically. Using JCMT SCUBA-2 archival data, we surveyed 70 fields that target high-latitude Planck galactic cold clumps (HLPCs) to find dense cores with density of $10^{5}$-$10^{6}$ cm$^{-3}$ and size of $<0.1$ pc. The sample benefits from both the representativeness of the parent sample and covering densest clumps at the high column density end ($>1\times10^{21}$ cm$^{-2}$). At an average noise rms of 15 mJy/beam, we detected Galactic dense cores in only one field, G6.04+36.77 (L183), while also identifying 12 extragalactic objects and two young stellar objects. Compared to the low-latitude clumps, dense cores are scarce in HLPCs. With synthetic observations, the densities of cores are constrained to be $n_c\lesssim10^5$ cm$^{-3}$, should they exist in HLPCs. Low-latitude clumps, Taurus clumps, and HLPCs form a sequence where a higher virial parameter corresponds to a lower dense core detection rate. If HLPCs were affected by the Local Bubble, the scarcity should favor turbulence-inhibited rather than supernova-driven star formation. Studies of the formation mechanism of the L183 molecular cloud are warranted., Comment: 9 pages for the main text. 4 figures, 1 table. Published in Astrophysical Journal Letter
- Published
- 2024
- Full Text
- View/download PDF
33. Dynamical Generation of the Baryon Asymmetry from a Scale Hierarchy
- Author
-
Chang, Jae Hyeok, Jeong, Kwang Sik, Lee, Chang Hyeon, and Shin, Chang Sub
- Subjects
High Energy Physics - Phenomenology - Abstract
We propose a novel baryogenesis scenario where the baryon asymmetry originates directly from a hierarchy between two fundamental mass scales: the electroweak scale and the Planck scale. Our model is based on the neutrino-portal Affleck-Dine (AD) mechanism, which generates the asymmetry of the AD sector during the radiation-dominated era and subsequently transfers it to the baryon number before the electroweak phase transition. The observed baryon asymmetry is then a natural outcome of this scenario. The model is testable as it predicts the existence of a Majoron with a keV mass and an electroweak scale decay constant. The impact of the relic Majoron on $\Delta N_{\rm eff}$ can be measured through near-future CMB observations., Comment: 5+5 pages, 2+1 figures. v2:references added, discussion extended
- Published
- 2024
34. Filamentary Network and Magnetic Field Structures Revealed with BISTRO in the High-Mass Star-Forming Region NGC2264 : Global Properties and Local Magnetogravitational Configurations
- Author
-
Wang, Jia-Wei, Koch, Patrick M., Clarke, Seamus D., Fuller, Gary, Peretto, Nicolas, Tang, Ya-Wen, Yen, Hsi-Wei, Lai, Shih-Ping, Ohashi, Nagayoshi, Arzoumanian, Doris, Johnstone, Doug, Furuya, Ray, Inutsuka, Shu-ichiro, Lee, Chang Won, Ward-Thompson, Derek, Gouellec, Valentin J. M. Le, Liu, Hong-Li, Fanciullo, Lapo, Hwang, Jihye, Pattle, Kate, Poidevin, Frédérick, Tahani, Mehrnoosh, Onaka, Takashi, Rawlings, Mark G., Chung, Eun Jung, Liu, Junhao, Lyo, A-Ran, Priestley, Felix, Hoang, Thiem, Tamura, Motohide, Berry, David, Bastien, Pierre, Ching, Tao-Chung, Coudé, Simon, Kwon, Woojin, Chen, Mike, Eswaraiah, Chakali, Soam, Archana, Hasegawa, Tetsuo, Qiu, Keping, Bourke, Tyler L., Byun, Do-Young, Chen, Zhiwei, Chen, Huei-Ru Vivien, Chen, Wen Ping, Cho, Jungyeon, Choi, Minho, Choi, Yunhee, Choi, Youngwoo, Chrysostomou, Antonio, Dai, Sophia, Di Francesco, James, Diep, Pham Ngoc, Doi, Yasuo, Duan, Yan, Duan, Hao-Yuan, Eden, David, Fiege, Jason, Fissel, Laura M., Franzmann, Erica, Friberg, Per, Friesen, Rachel, Gledhill, Tim, Graves, Sarah, Greaves, Jane, Griffin, Matt, Gu, Qilao, Han, Ilseung, Hayashi, Saeko, Houde, Martin, Inoue, Tsuyoshi, Iwasaki, Kazunari, Jeong, Il-Gyo, Könyves, Vera, Kang, Ji-hyun, Kang, Miju, Karoly, Janik, Kataoka, Akimasa, Kawabata, Koji, Khan, Zacariyya, Kim, Mi-Ryang, Kim, Kee-Tae, Kim, Kyoung Hee, Kim, Shinyoung, Kim, Jongsoo, Kim, Hyosung, Kim, Gwanjeong, Kirchschlager, Florian, Kirk, Jason, Kobayashi, Masato I. N., Kusune, Takayoshi, Kwon, Jungmi, Lacaille, Kevin, Law, Chi-Yan, Lee, Sang-Sung, Lee, Hyeseung, Lee, Jeong-Eun, Lee, Chin-Fei, Li, Dalei, Li, Hua-bai, Li, Guangxing, Li, Di, Lin, Sheng-Jun, Liu, Tie, Liu, Sheng-Yuan, Lu, Xing, Mairs, Steve, Matsumura, Masafumi, Matthews, Brenda, Moriarty-Schieven, Gerald, Nagata, Tetsuya, Nakamura, Fumitaka, Nakanishi, Hiroyuki, Ngoc, Nguyen Bich, Park, Geumsook, Parsons, Harriet, Pyo, Tae-Soo, Qian, Lei, Rao, Ramprasad, Rawlings, Jonathan, Retter, Brendan, Richer, John, Rigby, Andrew, Sadavoy, Sarah, Saito, Hiro, Savini, Giorgio, Seta, Masumichi, Sharma, Ekta, Shimajiri, Yoshito, Shinnaga, Hiroko, Tang, Xindi, Thuong, Hoang Duc, Tomisaka, Kohji, Tram, Le Ngoc, Tsukamoto, Yusuke, Viti, Serena, Wang, Hongchi, Whitworth, Anthony, Wu, Jintai, Xie, Jinjin, Yang, Meng-Zhe, Yoo, Hyunju, Yuan, Jinghua, Yun, Hyeong-Sik, Zenko, Tetsuya, Zhang, Chuan-Peng, Zhang, Yapeng, Zhang, Guoyin, Zhou, Jianjun, Zhu, Lei, de Looze, Ilse, André, Philippe, Dowell, C. Darren, Eyres, Stewart, Falle, Sam, Robitaille, Jean-François, and van Loo, Sven
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
We report 850 $\mu$m continuum polarization observations toward the filamentary high-mass star-forming region NGC 2264, taken as part of the B-fields In STar forming Regions Observations (BISTRO) large program on the James Clerk Maxwell Telescope (JCMT). These data reveal a well-structured non-uniform magnetic field in the NGC 2264C and 2264D regions with a prevailing orientation around 30 deg from north to east. Field strengths estimates and a virial analysis for the major clumps indicate that NGC 2264C is globally dominated by gravity while in 2264D magnetic, gravitational, and kinetic energies are roughly balanced. We present an analysis scheme that utilizes the locally resolved magnetic field structures, together with the locally measured gravitational vector field and the extracted filamentary network. From this, we infer statistical trends showing that this network consists of two main groups of filaments oriented approximately perpendicular to one another. Additionally, gravity shows one dominating converging direction that is roughly perpendicular to one of the filament orientations, which is suggestive of mass accretion along this direction. Beyond these statistical trends, we identify two types of filaments. The type-I filament is perpendicular to the magnetic field with local gravity transitioning from parallel to perpendicular to the magnetic field from the outside to the filament ridge. The type-II filament is parallel to the magnetic field and local gravity. We interpret these two types of filaments as originating from the competition between radial collapsing, driven by filament self-gravity, and the longitudinal collapsing, driven by the region's global gravity., Comment: Accepted for publication in the Astrophysical Journal. 43 pages, 32 figures, and 4 tables (including Appendix)
- Published
- 2024
35. The ALMA-QUARKS survey: Detection of two extremely dense substructures in a massive prestellar core
- Author
-
Mai, Xiaofeng, Liu, Tie, Liu, Xunchuan, Zhu, Lei, Garay, Guido, Goldsmith, Paul F., Juvela, Mika, Liu, Hongli, Mannfors, Emma, Tej, Anandmayee, Sanhueza, Patricio, Li, Shanghuo, Xu, Fengwei, Semadeni, Enrique Vazquez, Jiao, Wenyu, Peng, Yaping, Baug, T., Yang, Aiyuan, Dewangan, Lokesh, Bronfman, Leonardo, Gómez, Gilberto C., Palau, Aina, Lee, Chang Won, Qin, Sheng-Li, Tatematsu, Ken'ichi, Chibueze, James O., Yang, Dongting, Lu, Xing, Luo, Qiuyi, Gu, Qilao, Issac, Namitha, Zhang, Suinan, Li, Pak-Shing, Zhang, Bo, and Tóth, L. Viktor
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Only a handful of massive starless core candidates have been discovered so far, but none of them have been fully confirmed. Within the MM1 clump in the filamentary infrared dark cloud G34.43+0.24 that was covered by the ALMA-ATOMS survey at Band 3 ($\sim2\arcsec$, 6000\,au) and the ALMA-QUARKS survey at Band 6 ($\sim 0.3\arcsec$, 900\,au), two prestellar core candidates MM1-C and E1 with masses of 71 and 20 \solarmass~and radii of 2100--4400\,au were discovered. The two cores show no obvious sign of star-formation activities. In particular, MM1-C is a very promising massive prestellar core candidate with a total gas mass of 71\,\solarmass. Within MM1-C, we detected two extremely dense substructures, C1 and C2, as characterized by their high densities of $\rm n_{H_2}\sim 10^{8-9} cm^{-3}$. Moreover, evidence of further fragmentation in C2 was also revealed. We have detected the primordial fragmentation in the earliest stage of massive star formation, and we speculate that MM1-C would be the birthplace of a massive multiple system. However, we cannot fully rule out the possibility that the massive prestellar core MM1-C will just form a cluster of low-mass stars if it undergoes further fragmentation., Comment: 12 pages, 6 figures
- Published
- 2024
36. {\alpha}-decay half-lives for even-even isotopes of W to U
- Author
-
Choi, Yong-Beom, Lee, Chang-Hwan, Mun, Myeong-Hwan, Choi, Soonchul, and Kim, Youngman
- Subjects
Nuclear Theory - Abstract
We investigate {\alpha}-decay half-lives for 74 {\le} Z {\le} 92 even-even nuclei within the semiclassical WKB approximation in deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). The {\alpha}-particle preformation factors are estimated from cluster-formation model using both empirical AME2020 binding energies and numerical ones obtained by a deep neural network (DNN) study in which available DRHBc binding energies are used as training set. We find that our estimated {\alpha}-decay half-lives are qualitatively in agree with experimental results. We also compare our results with the empirical formulae, ZZCW and UNIV. Based on these observation, we extend our predictions of {\alpha}-decay half-lives for the isotopes whose experimental data are not available., Comment: 19 pages, 9 figures
- Published
- 2023
37. Purcell enhanced emission and saturable absorption of cavity-coupled CsPbBr$_3$ quantum dots
- Author
-
Purkayastha, Purbita, Gallagher, Shaun, Jiang, Yuxi, Lee, Chang-Min, Shen, Gillian, Ginger, David, and Waks, Edo
- Subjects
Physics - Optics ,Physics - Applied Physics - Abstract
Halide perovskite semiconductors have emerged as promising materials for the development of solution-processed, scalable, high performance optoelectronic devices such as light-emitting diodes (LEDs) as well as coherent single photon emitters. Their integration to nanophotonic cavities for radiative enhancement and strong nonlinearity is underexplored. In this work, we demonstrate cavity-enhanced emission and saturable absorption using colloidal CsPbBr$_3$ perovskite quantum dots coupled to a high-Q cavity mode of a circular Bragg grating structure designed to facilitate integration of solution-processed materials . We achieve an order of magnitude increase in brightness and 8-fold increase in the spontaneous emission rate for the cavity-coupled emitters. This result indicates the possibility of achieving transform-limited photon coherence for the halide perovskites at cryogenic temperatures. We also observe saturable absorption of the emitters through intensity-dependent cavity quality factor. These results pave the way towards achieving improved photon indistinguishability and strong optical nonlinearities for cavity coupled perovskite systems., Comment: 10 pages, 4 figures
- Published
- 2023
38. Optimizing the quality factor of InP nanobeam cavities using atomic layer deposition
- Author
-
Rahaman, Mohammad Habibur, Lee, Chang-Min, Buyukkaya, Mustafa Atabey, Harper, Samuel, Islam, Fariba, and Waks, Edo
- Subjects
Physics - Optics ,Physics - Applied Physics - Abstract
Photonic crystal nanobeam cavities are valued for their small mode volume, CMOS compatibility, and high coupling efficiency crucial features for various low-power photonic applications and quantum information processing. However, despite their potential, nanobeam cavities often suffer from low quality factors due to fabrication imperfections that create surface states and optical absorption. In this work, we demonstrate InP nanobeam cavities with up to 140% higher quality factors by applying a coating of Al$_2$O$_3$ via atomic layer deposition to terminate dangling bonds and reduce surface absorption. Additionally, changing the deposition thickness allows precise tuning of the cavity mode wavelength without compromising the quality factor. This Al$_2$O$_3$ atomic layer deposition approach holds great promise for optimizing nanobeam cavities that are well-suited for integration with a wide range of photonic applications.
- Published
- 2023
39. Osteoporosis Prediction from Hand and Wrist X-rays using Image Segmentation and Self-Supervised Learning
- Author
-
Lee, Hyungeun, Hwang, Ung, Yu, Seungwon, Lee, Chang-Hun, and Yoon, Kijung
- Subjects
Electrical Engineering and Systems Science - Image and Video Processing ,Computer Science - Computer Vision and Pattern Recognition - Abstract
Osteoporosis is a widespread and chronic metabolic bone disease that often remains undiagnosed and untreated due to limited access to bone mineral density (BMD) tests like Dual-energy X-ray absorptiometry (DXA). In response to this challenge, current advancements are pivoting towards detecting osteoporosis by examining alternative indicators from peripheral bone areas, with the goal of increasing screening rates without added expenses or time. In this paper, we present a method to predict osteoporosis using hand and wrist X-ray images, which are both widely accessible and affordable, though their link to DXA-based data is not thoroughly explored. Initially, our method segments the ulnar, radius, and metacarpal bones using a foundational model for image segmentation. Then, we use a self-supervised learning approach to extract meaningful representations without the need for explicit labels, and move on to classify osteoporosis in a supervised manner. Our method is evaluated on a dataset with 192 individuals, cross-referencing their verified osteoporosis conditions against the standard DXA test. With a notable classification score (AUC=0.83), our model represents a pioneering effort in leveraging vision-based techniques for osteoporosis identification from the peripheral skeleton sites., Comment: Extended Abstract presented at Machine Learning for Health (ML4H) symposium 2023, December 10th, 2023, New Orleans, United States, 10 pages
- Published
- 2023
40. ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Discovery of an extremely dense and compact object embedded in the prestellar core G208.68-19.92-N2
- Author
-
Hirano, Naomi, Sahu, Dipen, Liu, Sheng-Yaun, Liu, Tie, Tatematsu, Ken'ichi, Dutta, Somnath, Li, Shanghuo, Lee, Chin-Fei, Li, Pak Shing, Hsu, Shih-Ying, Lin, Sheng-Jun, Johnstone, Doug, Bronfman, Leonardo, Chen, Huei-Ru Vivien, Eden, David J., Kuan, Yi-Jehng, Kwon, Woojin, Lee, Chang Won, Liu, Hong-Li, Rawlings, Mark G., Ristorcelli, Isabelle, and Traficante, Alessio
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
The internal structure of the prestellar core G208.68-19.02-N2 (G208-N2) in the Orion Molecular Cloud 3 (OMC-3) region has been studied with the Atacama Large Millimeter/submillimeter Array (ALMA). The dust continuum emission revealed a filamentary structure with a length of $\sim$5000 au and an average H$_2$ volume density of $\sim$6 $\times$ 10$^7$ cm$^{-3}$. At the tip of this filamentary structure, there is a compact object, which we call a ``nucleus", with a radius of $\sim$150--200 au and a mass of $\sim$0.1 M$_{\odot}$. The nucleus has a central density of $\sim$2 $\times$ 10$^9$ cm$^{-3}$ with a radial density profile of $r^{-1.87{\pm}0.11}$. The density scaling of the nucleus is $\sim$3.7 times higher than that of the singular isothermal sphere. This as well as the very low virial parameter of 0.39 suggest that the gravity is dominant over the pressure everywhere in the nucleus. However, there is no sign of CO outflow localized to this nucleus. The filamentary structure is traced by the N$_2$D$^+$ 3--2 emission, but not by the C$^{18}$O 2--1 emission, implying the significant CO depletion due to high density and cold temperature. Toward the nucleus, the N$_2$D$^+$ also shows the signature of depletion. This could imply either the depletion of the parent molecule, N$_2$, or the presence of the embedded very-low luminosity central source that could sublimate the CO in the very small area. The nucleus in G208-N2 is considered to be a prestellar core on the verge of first hydrostatic core (FHSC) formation or a candidate for the FHSC., Comment: 27 pages, 16 figures
- Published
- 2023
41. Telecom band quantum dot technologies for long-distance quantum networks
- Author
-
Yu, Ying, Liu, Shunfa, Lee, Chang-Min, Michler, Peter, Reitzenstein, Stephan, Srinivasan, Kartik, Waks, Edo, and Liu, Jin
- Subjects
Quantum Physics - Abstract
A future quantum internet is expected to generate, distribute, store and process quantum bits (qubits) over the globe by linking different quantum nodes via quantum states of light. To facilitate the long-haul operations, quantum repeaters, the building blocks for a long-distance quantum network, have to be operated in the telecom wavelengths to take advantage of both the low-loss fiber network and the well-established technologies for optical communications. Semiconductors quantum dots (QDs) so far have exhibited exceptional performances as key elements, i.e., quantum light sources and spin-photon interfaces, for quantum repeaters, but only in the near-infrared (NIR) regime. Therefore, the development of high-performance telecom-band QD devices is highly desirable for a future solid-state quantum internet based on fiber networks. In this review, we present the physics and the technological developments towards epitaxial QD devices emitting at the telecom O- and C-bands for quantum networks by using advanced epitaxial growth for direct telecom emission, and quantum frequency conversion (QFC) for telecom-band down-conversion. We also discuss the challenges and opportunities in the future to realize telecom QD devices with improved performances and expanded functionalities by taking advantage of hybrid integrations., Comment: Final version to appear in Nature Nano
- Published
- 2023
42. Field-Weakening Control Method on Induction Motor of Low-Speed Vehicle Using Look-Up Tables
- Author
-
Lee, EunWoo, Choi, DongHo, Lee, Chang-Hee, and Lee, June-Seok
- Published
- 2024
- Full Text
- View/download PDF
43. Performance Analysis of a Ducted Rocket Under Various Flight Conditions
- Author
-
Lee, Yong-Kun, Sung, Hong-Gye, and Lee, Chang-Hun
- Published
- 2024
- Full Text
- View/download PDF
44. Impact of artificial sweeteners and rare sugars on the gut microbiome
- Author
-
Lee, Chang-Young, So, Yun-Sang, Yoo, Sang-Ho, Lee, Byung-Hoo, and Seo, Dong-Ho
- Published
- 2024
- Full Text
- View/download PDF
45. A computational model for sample dependence in hypothesis testing of genome data
- Author
-
Kim, Sunhee and Lee, Chang-Yong
- Published
- 2024
- Full Text
- View/download PDF
46. A Study on the Weapon–Target Assignment Problem Considering Heading Error
- Author
-
Kim, Ji-Eun, Lee, Chang-Hun, and Yi, Mun Yong
- Published
- 2024
- Full Text
- View/download PDF
47. Monitoring activity in Mount Melbourne, Antarctica, by multi-temporal SAR interferometry based on the ICOPS algorithm
- Author
-
Hakim, Wahyu L., Sakina, Raisa N., Fadhillah, Muhammad F., Lee, Seulki, Park, Sungjae, Kim, Hyun-Cheol, and Lee, Chang-Wook
- Published
- 2024
- Full Text
- View/download PDF
48. Pressure Ulcer Breakout Time Estimation Model for the Wearable Robot Use
- Author
-
Lee, Chang-Hwan and Gwak, Kwan-Woong
- Published
- 2024
- Full Text
- View/download PDF
49. Chronoamperometric determination of the diffusion coefficient in molten chlorides
- Author
-
Kim, In Ui, Kim, Junhyeong, Lee, Chang Hwa, and Cho, Sung Ki
- Published
- 2024
- Full Text
- View/download PDF
50. Vaccination induces broadly neutralizing antibody precursors to HIV gp41
- Author
-
Schiffner, Torben, Phung, Ivy, Ray, Rashmi, Irimia, Adriana, Tian, Ming, Swanson, Olivia, Lee, Jeong Hyun, Lee, Chang-Chun D., Marina-Zárate, Ester, Cho, So Yeon, Huang, Jiachen, Ozorowski, Gabriel, Skog, Patrick D., Serra, Andreia M., Rantalainen, Kimmo, Allen, Joel D., Baboo, Sabyasachi, Rodriguez, Oscar L., Himansu, Sunny, Zhou, Jianfu, Hurtado, Jonathan, Flynn, Claudia T., McKenney, Katherine, Havenar-Daughton, Colin, Saha, Swati, Shields, Kaitlyn, Schultze, Steven, Smith, Melissa L., Liang, Chi-Hui, Toy, Laura, Pecetta, Simone, Lin, Ying-Cing, Willis, Jordan R., Sesterhenn, Fabian, Kulp, Daniel W., Hu, Xiaozhen, Cottrell, Christopher A., Zhou, Xiaoya, Ruiz, Jennifer, Wang, Xuesong, Nair, Usha, Kirsch, Kathrin H., Cheng, Hwei-Ling, Davis, Jillian, Kalyuzhniy, Oleksandr, Liguori, Alessia, Diedrich, Jolene K., Ngo, Julia T., Lewis, Vanessa, Phelps, Nicole, Tingle, Ryan D., Spencer, Skye, Georgeson, Erik, Adachi, Yumiko, Kubitz, Michael, Eskandarzadeh, Saman, Elsliger, Marc A., Amara, Rama R., Landais, Elise, Briney, Bryan, Burton, Dennis R., Carnathan, Diane G., Silvestri, Guido, Watson, Corey T., Yates, III, John R., Paulson, James C., Crispin, Max, Grigoryan, Gevorg, Ward, Andrew B., Sok, Devin, Alt, Frederick W., Wilson, Ian A., Batista, Facundo D., Crotty, Shane, and Schief, William R.
- Published
- 2024
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.