• Title/Summary/Keyword: Physical feature

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The Spatially Closed Universe

  • Park, Chan-Gyung
    • Journal of the Korean earth science society
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    • v.40 no.4
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    • pp.353-381
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    • 2019
  • The general world model for homogeneous and isotropic universe has been proposed. For this purpose, we introduce a global and fiducial system of reference (world reference frame) constructed on a (4+1)-dimensional space-time, and assume that the universe is spatially a 3-dimensional hypersurface embedded in the 4-dimensional space. The simultaneity for the entire universe has been specified by the global time coordinate. We define the line element as the separation between two neighboring events on the expanding universe that are distinct in space and time, as viewed in the world reference frame. The information that determines the kinematics of the geometry of the universe such as size and expansion rate has been included in the new metric. The Einstein's field equations with the new metric imply that closed, flat, and open universes are filled with positive, zero, and negative energy, respectively. The curvature of the universe is determined by the sign of mean energy density. We have demonstrated that the flat universe is empty and stationary, equivalent to the Minkowski space-time, and that the universe with positive energy density is always spatially closed and finite. In the closed universe, the proper time of a comoving observer does not elapse uniformly as judged in the world reference frame, in which both cosmic expansion and time-varying light speeds cannot exceed the limiting speed of the special relativity. We have also reconstructed cosmic evolution histories of the closed world models that are consistent with recent astronomical observations, and derived useful formulas such as energy-momentum relation of particles, redshift, total energy in the universe, cosmic distance and time scales, and so forth. The notable feature of the spatially closed universe is that the universe started from a non-singular point in the sense that physical quantities have finite values at the initial time as judged in the world reference frame. It has also been shown that the inflation with positive acceleration at the earliest epoch is improbable.

A Study on RFID Privacy Protection in Insecure Channel (안전하지 않은 채널에서의 RFID 프라이버시 보호에 관한 연구)

  • Park Jang-Su;Lee Im-Yeong
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.16 no.3
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    • pp.77-86
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    • 2006
  • As a core technology in the ubiquitous environment, RFID (Radio Frequency Identification) technology takes an important role. RFID technology provides various information about objects or surrounding environment by attaching a small electronic tag on the object, thus, it means the remote control recognition technology. However, the problems which never happened before can be generated on the point of security and privacy due to the feature that RFID technology can recognize the object without any physical contact. In order to solve these problems, many studies for the RFID recognition technology are going on the progress. The currently running study is the secure communication channel between database and reader applying the recognition technology in the insecure communication channel between reader and tag. But, the purpose of this paper is to settle a privacy problem, which is insecurity of communication between database and reader channel by suggesting providing a user with authentication protocol in order to give information to an authorized entity.

The Effect of Security Information Sharing and Disruptive Technology on Patient Dissatisfaction in Saudi Health Care Services During Covid-19 Pandemic

  • Beyari, Hasan;Hejazi, Mohammed;Alrusaini, Othman
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.10
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    • pp.3313-3332
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    • 2022
  • This study is an investigation into the factors affecting patient dissatisfaction among Saudi hospitals. The selected factors considered for analysis are security of information sharing, operational practices, disruptive technologies, and the ease of use of EHR patient information management systems. From the literature review section, it was clear that hardly any other studies have embraced these concepts in one as was intended by this study. The theories that the study heavily draws from are the service dominant logic and the feature integration theory. The study surveyed 350 respondents from three large major hospitals in three different metropolitan cities in the Kingdom of Saudi Arabia. This sample came from members of the three hospitals that were willing to participate in the study. The number 350 represents those that successfully completed the online questionnaire or the limited physical questionnaires in time. The study employed the structural equation modelling technique to analyze the associations. Findings suggested that security of information sharing had a significant direct effect on patient satisfaction. Operational practice positively mediated the effect of security of information sharing on patient dissatisfaction. However, ease of use failed to significant impact this association. The study concluded that to improve patient satisfaction, Saudi hospitals must work on their systems to reinforce them against the active threats on the privacy of patients' data by leveraging disruptive technology. They should also improve their operational practices by embracing quality management techniques relevant to the healthcare sector.

An Analytical Study on Space Configuration in After-School Care Class for Elementary School - Focused on Guidelines of Emementary School Care Classes - (초등돌봄교실 공간구성특징에 관한 분석연구 - 초등 돌봄교실 길라잡이를 중심으로 -)

  • Kim, Sora
    • Journal of the Korean Institute of Educational Facilities
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    • v.28 no.6
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    • pp.3-13
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    • 2021
  • Introduced in 2004 as an 'After-School Academy' policy, the 'After-School Care Class' has become a universal program for elementary schools over time. While the concept of public education service has expanded and changed in various ways including educational welfare, the physical environment of the care classroom has undergone fixed changes within the uniform classroom structure of a standardized school space. The purpose of this study is to identify spatial characteristics of care classroom through chasing and analysing changes in the care class space configuration from 2004 to the present. The findings are as follows. The plan of the early care classroom wasn't much different from the existing common classroom, and it was only in 2007 that the kitchen and floor heating appeared for the first time.From the 2015 standard plan, prominent differentiation of the space between learning activities and resting area was shown, but the spatial characteristics are nothing more than a division that utilizes ready-made furniture. A distinctive feature of the 2018 Seoul care classes are diversity. In the case of the care exclusive classrooms, the division between the support space and the main activity space became more clear using furniture integrated open walls and various floor levels. In the case of a shift classrooms that is used together with common classrooms, it is characterized by flexibility that allows dramatically different classroom configurations for each time period by using a convertible furnishing space.

The Influence of Characteristics of Beauty Influencers' Social Media Contents on Color Cosmetics Purchase Intention - Focusing on the Millennial Generation - (뷰티인플루언서의 뷰티콘텐츠특성이 색조화장품 구매의도에 미치는 영향 - 밀레니얼세대를 중심으로 -)

  • Eun-Seo Heo;Hyun-jin Jeon
    • Fashion & Textile Research Journal
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    • v.25 no.1
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    • pp.104-112
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    • 2023
  • This study attempted to investigate the characteristics of beauty influencers' social media contents and examine their influence on color cosmetics purchase intention. For this, female millennials who have shown an interest or subscribed beauty contents on social media platforms as followers were selected by convenience sampling. In terms of a research method, a self-administered questionnaire was performed from September 19 to 30, 2022. Among a total of 220 questionnaires distributed, 200 copies excluding poorly answered ones were used for final analysis. The collected data were analyzed by frequency analysis, descriptive statistics, factor analysis, reliability analysis, correlation analysis and multiple regression analysis, using SPSS 24.0, and the results found the followings: First, concerning characteristics of beauty influencers' beauty contents, five factors were derived: reliability, professionalism, social attractiveness, attractive appearance, sympathy In purchase intention, on the contrary, two factors were obtained: base makeup, point makeup. Second, regarding the effects of characteristics of beauty contents on color cosmetics purchase intention, 'professionalism (β = -.170 p = .015)' and 'physical attractiveness (β = -.148, p = .037)' revealed a negative influence with statistical significance. Through the result, by demonstrating the effect on the intention to purchase color cosmetics based on the beauty contents feature of the beauty influencer, it is considered that the purchasing power of the color cosmetics industry will continue to increase and help to suggest more effective color cosmetics promotion ways and indicators which companies can utilize.

Feasibility and reliability of various morphologic features on magnetic resonance imaging for iliotibial band friction syndrome

  • Jin Kyem Kim;Taeho Kim;Hong Seon Lee;Dong Kyu Kim
    • The Korean Journal of Pain
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    • v.36 no.2
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    • pp.208-215
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    • 2023
  • Background: To evaluate the feasibility, inter-reader reliability, and intra-reader reliability for various morphological features reported to be related to iliotibial band friction syndrome (ITBFS) on knee magnetic resonance imaging (MRI). Methods: A total of 145 patients with a clinical diagnosis and knee MRI findings consistent with ITBFS were included in the "study group" and 232 patients without knee pathology on both physical examination and MRI were included in the "control group". Various morphologic features on knee MRI were assessed including the patella shape, patella height, lateral epicondyle anterior-posterior (AP) width, lateral epicondyle height, ITB diameter (ITB-d), and ITB area (ITB-a). Results: Patients in the study group had significantly higher lateral epicondyle height (13.9 mm vs. 12.92 mm, P = 0.003), ITB-d (2.9 mm vs. 2.0 mm, P = 0.022), and ITB-a (38.5 mm2 vs. 23.8 mm2, P < 0.001) than the control group. ITB-a showed higher area under the curve index (0.849 with 74.1% sensitivity and 72.4% specificity at a 30.3 mm2 cutoff) than ITB-d (0.710 with 70.8% sensitivity and 61.2% specificity at 2.4 mm cutoff) and lateral epicondyle height (0.776 with 72.4% sensitivity and 67.8% specificity at 13.4 mm cutoff). However, only the inter-reader agreement for ITB-a (intraclass correlation coefficient = 0.65) was moderate, while the agreements for other morphologic features were good or excellent. Conclusions: Lateral epicondyle height seems to be a reliable and feasible morphologic feature for diagnosis of ITBFS.

Implementation of a Wearable Device for Monitoring the Health Status of the Elderly Living Alone

  • Ji-Hoon Lee;Gyung-Hwan Kim;Myeong-Chul Park
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.5
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    • pp.39-46
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    • 2024
  • In this paper, we propose a low-cost wearable device that can monitor the health status of the elderly living alone in real-time. As aging is accelerating, the elderly population is rapidly increasing, and the social isolation of the elderly living alone is causing physical and mental difficulties and the number of elderly people dying alone is increasing, becoming a social problem. In this study, we propose a belly band-type wearable device that can monitor the biometric information of elderly living alone. The proposed device transmits electromyogram, electrocardiogram, and body temperature information to a remote server through an Arduino-based sensor built into the abdominal band. Transmitted information can be monitored in a web environment in real-time, and it has the feature of enabling remote monitoring of a large number of subjects with a small amount of management manpower. The research results will contribute to improving the safety and welfare of seniors living alone by not only detecting lonely deaths in advance but also responding immediately to dangerous situations that may occur in daily life.

Deep learning-based AI constitutive modeling for sandstone and mudstone under cyclic loading conditions

  • Luyuan Wu;Meng Li;Jianwei Zhang;Zifa Wang;Xiaohui Yang;Hanliang Bian
    • Geomechanics and Engineering
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    • v.37 no.1
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    • pp.49-64
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    • 2024
  • Rocks undergoing repeated loading and unloading over an extended period, such as due to earthquakes, human excavation, and blasting, may result in the gradual accumulation of stress and deformation within the rock mass, eventually reaching an unstable state. In this study, a CNN-CCM is proposed to address the mechanical behavior. The structure and hyperparameters of CNN-CCM include Conv2D layers × 5; Max pooling2D layers × 4; Dense layers × 4; learning rate=0.001; Epoch=50; Batch size=64; Dropout=0.5. Training and validation data for deep learning include 71 rock samples and 122,152 data points. The AI Rock Constitutive Model learned by CNN-CCM can predict strain values(ε1) using Mass (M), Axial stress (σ1), Density (ρ), Cyclic number (N), Confining pressure (σ3), and Young's modulus (E). Five evaluation indicators R2, MAPE, RMSE, MSE, and MAE yield respective values of 0.929, 16.44%, 0.954, 0.913, and 0.542, illustrating good predictive performance and generalization ability of model. Finally, interpreting the AI Rock Constitutive Model using the SHAP explaining method reveals that feature importance follows the order N > M > σ1 > E > ρ > σ3.Positive SHAP values indicate positive effects on predicting strain ε1 for N, M, σ1, and σ3, while negative SHAP values have negative effects. For E, a positive value has a negative effect on predicting strain ε1, consistent with the influence patterns of conventional physical rock constitutive equations. The present study offers a novel approach to the investigation of the mechanical constitutive model of rocks under cyclic loading and unloading conditions.

The Superior Approach in Hemiarthroplasty for Femoral Neck Fracture: A Comparative Analysis with the Posterior Approach

  • Kenta Kamo
    • Hip & pelvis
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    • v.36 no.3
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    • pp.211-217
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    • 2024
  • Purpose: The concept of a superior approach (SA) involves the use of a tissue-sparing posterior approach (PA), with exposure of the piriformis muscle and gluteus medius/minimus muscles. The objective of this study was to clarify the features of hip hemiarthroplasty (HA) using a SA in regard to early recovery and mid-term outcomes, with a comparison of the outcomes of SA-HAs and HAs using a PA (PA-HAs). Materials and Methods: A total of 120 HAs for treatment of primary femoral neck fracture with a healthy opposite hip joint were performed in our hospital from 2013 to 2018. Propensity score matching in regard to age, sex, body mass index, walking ability before injury, place of residence, time to surgery, and American Society of Anesthesiologists-Physical Status was performed for 79 patients with SA-HAs and 41 patients with PA-HAs. The final analysis included 34 patients who underwent SA-HAs and 34 patients who underwent PA-HAs. Results: The duration of surgery was 57.1 minutes and 72.1 minutes (P=0.001) for SA-HAs and PA-HAs, respectively. The scores for walking ability at postoperative one week were 4.9±1.4 and 4.2±1.0 (P=0.021) for SA-HAs and PA-HAs, respectively. The Barthel index (BI) at the start of rehabilitation was 26.2±18.7 and 17.4±16.3 (P=0.042) for SA-HAs and PA-HAs, respectively. The 4-year complication-free survival rates were 74.2% and 56.3% for SA-HAs and PA-HAs, respectively (P=0.310). Conclusion: SA-HA can be performed without torsion of the muscles and ligaments around the hip joint. Early recovery of walking ability and BI was a significant feature of SA-HAs.

Investigation of characteristic values in TDR waveform using SHapley Additive exPlanations (SHAP) for dielectric constant estimation during curing time

  • Won-Taek Hong;WooJin Han;Yong-Hoon Byun;Hyung-Koo Yoon
    • Smart Structures and Systems
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    • v.34 no.1
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    • pp.25-32
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    • 2024
  • As materials cure, the internal electrical flow changes, leading to variations in the dielectric constant over time. This study aims to assess the impact of voltage values extracted from time domain reflectometry (TDR) waveforms, measured during the curing of materials, on predicting the dielectric constant. The experiments are conducted over a curing period ranging from 60 to 8640 minutes, with 30 TDR trials. From the measured waveforms, values of V0, V1, V2, Vf, and Δt are deduced. Additionally, curing time is included as an input variable. Groups A and B are distinguished based on the presence or absence of Δt, indicating a physical relationship between Δt and the dielectric constant. The dielectric constant is set as the output variable. The SHapley Additive exPlanations (SHAP) algorithm is applied to the compiled data. The results indicate that Δt and V1 are the most influential input variables in both Group-A and Group-B. The study also presents the distribution of SHAP values and interacts SHAP values to infer the interrelationships among the input variables. To validate the reliability of these findings, the partial dependence (PD) algorithm is applied to estimate the marginal effects of each input variable, with outcomes closely aligning with those of the SHAP algorithm. This research suggests that understanding the contributions and proportional relationships of each input variable can aid in interpreting the relationships among various material properties.