• Biomedical Engineering Letters
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• v.8 no.4
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• pp.383-392
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• 2018

For prompt gamma ray imaging for biomedical applications and environmental radiation monitoring, we propose herein a multiple-scattering Compton camera (MSCC). MSCC consists of three or more semiconductor layers with good energy resolution, and has potential for simultaneous detection and differentiation of multiple radio-isotopes based on the measured energies, as well as three-dimensional (3D) imaging of the radio-isotope distribution. In this study, we developed an analytic simulator and a 3D image generator for a MSCC, including the physical models of the radiation source emission and detection processes that can be utilized for geometry and performance prediction prior to the construction of a real system. The analytic simulator for a MSCC records coincidence detections of successive interactions in multiple detector layers. In the successive interaction processes, the emission direction of the incident gamma ray, the scattering angle, and the changed traveling path after the Compton scattering interaction in each detector, were determined by a conical surface uniform random number generator (RNG), and by a Klein-Nishina RNG. The 3D image generator has two functions: the recovery of the initial source energy spectrum and the 3D spatial distribution of the source. We evaluated the analytic simulator and image generator with two different energetic point radiation sources (Cs-137 and Co-60) and with an MSCC comprising three detector layers. The recovered initial energies of the incident radiations were well differentiated from the generated MSCC events. Correspondingly, we could obtain a multi-tracer image that combined the two differentiated images. The developed analytic simulator in this study emulated the randomness of the detection process of a multiple-scattering Compton camera, including the inherent degradation factors of the detectors, such as the limited spatial and energy resolutions. The Doppler-broadening effect owing to the momentum distribution of electrons in Compton scattering was not considered in the detection process because most interested isotopes for biomedical and environmental applications have high energies that are less sensitive to Doppler broadening. The analytic simulator and image generator for MSCC can be utilized to determine the optimal geometrical parameters, such as the distances between detectors and detector size, thus affecting the imaging performance of the Compton camera prior to the development of a real system.

• Research in Community and Public Health Nursing
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• v.29 no.4
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• pp.450-466
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• 2018

Purpose: The purpose of this study is to identify trends in research on cultural competency of nursing students and nurses in Korea and to provide suggestions for future studies. Methods: A literature search was conducted with 432 papers published between 1985 and 2016 from five electronic databases and other sources using such key words as 'cultural competency', 'cultural nursing', 'multi-cultural competency', 'nursing students', 'nurses', etc. Results: The research design of 86 nursing researches on the cultural competence of nurses and nursing students analyzed in this study was 90.7% in quantitative research, 9.3% in qualitative research, and 2.3% in mixed research. Cultural competence was the most measured concept. A total of 41 papers (47.7%) out of 86 papers were used to measure cultural competence. Ten different tools were used various instruments of cultural competency were used in 41 papers. In 11 experimental studies, new methods such as role playing, case study, four stage 3D puzzle model, newspaper reading, and writing reflection note were used other than traditional method of lecture. Conclusion: The overall findings of this study suggest that future research should include more well-designed experimental studies, qualitative studies and repeated studies to confirm the effects of findings from previous studies. Development of effective and highly diverse teaching methods is recommended to increase cultural competency. Supporting systems and funding are required to help activate research of nurses.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.949-959
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• 2021

The current study aims to explore the shielding properties of multi-component borate-based glass series. Seven glass-samples with composition of (80-y)H₃BO₃-10ZnO-10Na₂O-yBaO where (y = 0, 5, 10, 15, 20, 25 and 30 mol.%) were synthesized by melt-quench method. Various shielding features for photons, neutrons, and protons were determined for all prepared samples. XCOM, Phy-X program, and SRIM code were performed to determine and explain several shielding properties such as equivalent atomic number, exposure build-up factor, specific gamma-ray constants, effective removal cross-section (Σ_R), neutron scattering and absorption, Mass Stopping Power (MSP) and projected range. The energy ranges for photons and protons were 0.015-15 MeV and 0.01-10 MeV, respectively. The mass attenuation coefficient (μ/ρ) was also determined experimentally by utilizing two radioactive sources (¹⁶⁶Ho and ¹³⁷Cs). Consistent results were obtained between experimental and XCOM values in determining μ/ρ of the new glasses. The addition of BaO to the glass matrix led to enhance the μ/ρ and specific gamma-ray constants of glasses. Whereas the remarkable reductions in Σ_R, MSP, and projected range values were reported with increasing BaO concentrations. The acquired results nominate the use of these glasses in different radiation shielding purposes.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.169-177
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• 2021

In this paper, we propose a novel global navigation satellite system (GNSS) spoofing detection technique through an array antenna-based direction of arrival (DoA) estimation of satellite and spoofer. Specifically, we consider a sophisticated GNSS spoofing attack scenario where the spoofer can accurately mimic the multiple pseudo-random number (PRN) signals since the spoofer has its own GNSS receiver and knows the location of the target receiver in advance. The target GNSS receiver precisely estimates the DoA of all PRN signals using compressed sensing-based orthogonal matching pursuit (OMP) even with a small number of samples, and it performs spoofing detection from the DoA estimation results of all PRN signals. In addition, considering the initial situation of a sophisticated spoofing attack scenario, we designed the algorithm to have high spoofing detection performance regardless of the relative spoofing signal power. Therefore, we do not consider the assumption in which the power of the spoofing signal is about 3 dB greater than that of the authentic signal. Then, we introduce design parameters to get high true detection probability and low false alarm probability in tandem by considering the condition for the presence of signal sources and the proximity of the DoA between authentic signals. Through computer simulations, we compare the DoA estimation performance between the conventional signal direction estimation method and the OMP algorithm in few samples. Finally, we show in the sophisticated spoofing attack scenario that the proposed spoofing detection technique using OMP-based estimated DoA of all PRN signals outperforms the conventional spoofing detection scheme in terms of true detection and false alarm probability.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.390-399
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• 2022

Cyber security and resilience are phrases that describe safeguards of ICTs (information and communication technologies) from cyber-attacks or mitigations of cyber event impacts. The sole purpose of Risk models are detections, analyses, and handling by considering all relevant perceptions of risks. The current research effort has resulted in the development of a new paradigm for safeguarding services offered online which can be utilized by both service providers and users. customers. However, rather of relying on detailed studies, this approach emphasizes task selection and execution that leads to successful risk treatment outcomes. Modelling intelligent CSGs (Cyber Security Games) using MLTs (machine learning techniques) was the focus of this research. By limiting mission risk, CSGs maximize ability of systems to operate unhindered in cyber environments. The suggested framework's main components are the Threat and Risk models. These models are tailored to meet the special characteristics of online services as well as the cyberspace environment. A risk management procedure is included in the framework. Risk scores are computed by combining probabilities of successful attacks with findings of impact models that predict cyber catastrophe consequences. To assess successful attacks, models emulating defense against threats can be used in topologies. CSGs consider widespread interconnectivity of cyber systems which forces defending all multi-step attack paths. In contrast, attackers just need one of the paths to succeed. CSGs are game-theoretic methods for identifying defense measures and reducing risks for systems and probe for maximum cyber risks using game formulations (MiniMax). To detect the impacts, the attacker player creates an attack tree for each state of the game using a modified Extreme Gradient Boosting Decision Tree (that sees numerous compromises ahead). Based on the findings, the proposed model has a high level of security for the web sources used in the experiment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.423-432
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• 2023

With the increasing demand for mobile devices featuring multi-touch operation, extensive research is being conducted on touch screen panel (TSP) Readout ICs (ROICs) that should possess low power consumption, compact chip size, and immunity to external noise. Therefore, this paper discusses capacitive touch sensors and their readout circuits, and it introduces research trends in various circuit designs that are robust against external noise sources. The recent state-of-the-art TSP ROICs have primarily focused on minimizing the impact of parasitic capacitance (Cp) caused by thin panel thickness. The large Cp can be effectively compensated using an area-efficient current compensator and Current Conveyor (CC), while a display noise reduction scheme utilizing a noise-antenna (NA) electrode significantly improves the signal-to-noise ratio (SNR). Based on these achievements, it is expected that future TSP ROICs will be capable of stable operation with thinner and flexible Touch Screen Panels (TSPs).

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.4
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• pp.127-134
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• 2023

This paper describes how to port the eCos operating system and PROFINET communication stack developed based on gcc to the IAR compiler. The eCos operating system provides basic functions such as multi-thread, TCP/IP, and device driver for PROFINET operation, so there is no need to change it when developing PROFINET applications. Therefore, in this study, we reuse an eCos library built with gcc and it link with PROFINET communication stack that are ported to IAR complier. Due to the different of the gcc and IAR linker, symbol definitions and address of the constructors should be changed using the external tool that generates symbol definitions and address of the constructors from MAP file. In order to verify the proposed method, it was confirmed that the actual I/O was operating normally through PROFINET IRT communication by connecting to the Siemens PLC. IAR compiler has better performance in both the compile time and the size of the generated binary. The proposed method in this study is expected to help port various open sources as well as eCos and PROFINET communication stacks to other compilers.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.50.2-51
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• 2021

Stars form exclusively in cold and dense molecular clouds. To fully understand star formation processes, it is hence a key to investigate how molecular clouds form out of the surrounding diffuse atomic gas. With an aim of shedding light in the process of the atomic-to-molecular transition in the interstellar medium, we analyze Arecibo HI emission and absorption spectral pairs along with TRAO/PMO 12CO(1-0) emission spectra toward 58 lines of sight probing in and around molecular clouds in the solar neighborhood, i.e., Perseus, Taurus, and California. 12CO(1-0) is detected from 19 out of 58 lines of sight, and we report the physical properties of HI (e.g., central velocity, spin temperature, and column density) in the vicinity of CO. Our preliminary results show that the velocity difference between the cold HI (Cold Neutral Medium or CNM) and CO (median ~ 0.7 km/s) is on average more than a factor of two smaller than the velocity difference between the warm HI (Warm Neutral Medium or WNM) and CO (median ~ 1.7 km/s). In addition, we find that the CNM tends to become colder (median spin temperature ~ 43 K) and abundant (median CNM fraction ~ 0.55) as it gets closer to CO. These results hints at the evolution of the CNM in the vicinity of CO, implying a close association between the CNM and molecular gas. Finally, in order to examine the role of HI in the formation of molecular gas, we compare the observed CNM properties to the theoretical model by Bialy & Sternberg (2016), where the HI column density for the HI-to-H2 transition point is predicted as a function of density, metallicity, and UV radiation field. Our comparison shows that while the model reproduces the observations reasonably well on average, the observed CNM components with high column densities are much denser than the model prediction. Several sources of this discrepancy, e.g., missing physical and chemical ingredients in the model such as the multi-phase ISM, non-equilibrium chemistry, and turbulence, will be discussed.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.2
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• pp.331-339
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• 2017

This paper proposes a thread pool management technique of an websocket server that is applicable to embedded systems. WebSocket is a proposed technique for consisting a dynamic web, and is constructed using HTML5 and jQuery. Various studies have been progressing to construct a dynamic web by Apache, Oracle and etc. Previous web service systems require high-capacity, high-performance hardware specifications and are not suitable for embedded systems. The node.js which is consist of HTML5 and jQuery is a typical websocket server which is made by open sources, and is a java script based web application which is composed of a single thread. The node.js has a limitation on the performance for processing a high velocity data on the embedded system. We make up a multi-thread based websoket server which can solve the mentioned problem. The thread pool is managed by a bit register and suitable for embedded systems. To evaluate the performance of the proposed algorithm, we uses JMeter that is a network test tool.

• Journal of the Korean Society of Food Culture
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• v.25 no.6
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• pp.725-733
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• 2010

This study examined the understanding and use of information on nutrition labels based on one serving size among female consumers above the age of 20 in Seoul area. According to the survey, 69.9% of respondents were aware of the current system of nutrition labeling based on one serving size, and 51.8% of the respondents expressed their dissatisfaction with the system because the nutrition labels were difficult to understand or appeared unreliable. The nutrition label literacy of the consumers varied with respect to different packaging units. The respondents were likely to be less accurate in calculating the expected caloric intake when only portions of a multi-serving package were used. Initially 69.0% of respondents reported that they had read the nutrition label before purchasing a product but 91.9% of respondents said that they would check the label after learning how to read the label properly. It is very important to make consumers aware that the labels are very reliable sources of nutrition information. A public education campaign on the use of nutrition labels should focus on developing the consumers' ability and skills in using the label information when choosing foods.