• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1061-1070
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• 2023

Over the last few years, lead-free inorganic metal perovskites have gained impressive ground in empowering satellites in space exploration owing to their material stability and performance evolution under extreme space environments. The present work has examined the versatility of eight such perovskites as space radiation shielding materials by computing their photon, charged particles and neutron interaction parameters. Photon interaction parameters were calculated for a wide energy range using PAGEX software. The ranges of heavy charged particles (H, He, C, N, O, Ne, Mg, Si and Fe ions) in these perovskites were estimated using SRIM software in the energy range 1 keV-10 GeV, and that of electrons was computed using ESTAR NIST software in the energy range 0.01 MeV-1 GeV. Further, the macroscopic fast neutron removal cross-sections were also calculated to estimate the neutron shielding efficiencies. The examined shielding parameters of the perovskites varied depending on the radiation type and energy. Among the selected perovskites, Cs₂TiI₆ and Ba₂AgIO₆ displayed superior photon attenuation properties. A 3.5 cm thick Ba₂AgIO₆-based shield could reduce the incident radiation intensity to half its initial value, a thickness even lesser than that of Pb-glass. Besides, CsSnBr₃ and La_0.8Ca_0.2Ni_0.5Ti_0.5O₃ displayed the highest and lowest range values, respectively, for all heavy charged particles. Ba₂AgIO₆ showed electron stopping power (on par with Kovar) better than that of other examined materials. Interestingly, La_0.8Ca_0.2Ni_0.5Ti_0.5O₃ demonstrated neutron removal cross-section values greater than that of standard neutron shielding materials - aluminium and polyethylene. On the whole, the present study not only demonstrates the employment prospects of eco-friendly perovskites for shielding space radiations but also suggests future prospects for research in this direction.

• Journal of Biomedical Engineering Research
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• v.45 no.1
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• pp.10-19
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• 2024

The purpose of this study is to conduct a summative evaluation of the usability of a general-purpose ventilator to determine whether it can be used for its intended purpose in the intended environment by the intended user and to find possible errors in use. The importance of ventilators has increased due to the accelerated aging of the population and the impact of the pandemic. In addition, patients who require ventilators are often in critical condition, so even a small error in use can be fatal. Therefore, it is important to ensure that the ventilator has sufficient stability and can be used satisfactorily without inconvenience to the user. In this study, we conducted a usability test with 17 respiratory nurses with more than 3 years of experience using the ventilator. We analyzed the task success rate, satisfaction, and opinions of the intended users while going through a total of 17 scenarios. Satisfaction was captured through an ASQ questionnaire and subjective opinions were captured through a detailed opinion questionnaire. The results showed a high level of satisfaction with an average score of 6.3 for the use scenarios. Evaluators expressed satisfaction with the overall visibility and versatility of the features, but noted that improvements were needed for calibration tasks with low task success rates. As the calibration method is different from other equipment, it was suggested that specific explanations of the calibration method and the picture that appears when calibrating are needed, and that if relevant training is provided, the equipment can be used without problems. If the usability evaluation is not limited to securing efficiency and satisfaction from the intended users, but also continuously receives feedback from users to prepare for use in emergency environments such as pandemic situations, it will be very helpful to seize opportunities such as emergency authorization in future situations, and ultimately contribute to patient safety by reducing use errors.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.1
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• pp.49-56
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• 2024

An automated dynamic structural analysis module stands as a crucial element within a structural integrated mitigation system. This module must deliver prompt real-time responses to enable timely actions, such as evacuation or warnings, in response to the severity posed by the structural system. The finite element method, a widely adopted approximate structural analysis approach globally, owes its popularity in part to its user-friendly nature. However, the computational efficiency and accuracy of results depend on the user-provided finite element mesh, with the number of elements and their quality playing pivotal roles. This paper introduces a computationally efficient adaptive mesh generation scheme that optimally combines the h-method of node movement and the r-method of element division for mesh refinement. Adaptive mesh generation schemes automatically create finite element meshes, and in this case, representative strain values for a given mesh are employed for error estimates. When applied to dynamic problems analyzed in the time domain, meshes need to be modified at each time step, considering a few hundred or thousand steps. The algorithm's specifics are demonstrated through a standard cantilever beam example subjected to a concentrated load at the free end. Additionally, a portal frame example showcases the generation of various robust meshes. These examples illustrate the adaptive algorithm's capability to produce robust meshes, ensuring reasonable accuracy and efficient computing time. Moreover, the study highlights the potential for the scheme's effective application in complex structural dynamic problems, such as those subjected to seismic or erratic wind loads. It also emphasizes its suitability for general nonlinear analysis problems, establishing the versatility and reliability of the proposed adaptive mesh generation scheme.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.67-78
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• 2024

Light absorption has potential as a signal in biochemical analyses due to its simplicity in measurement and interpretational clarity. Among substances that generate absorption signals, gold nanoparticles possess advantages such as chemical stability, biological compatibility, and unique optical properties from the localized surface plasmon resonance (LSPR) in the visible light range. They also exhibit versatility compared to other colorimetric substances effective only for specific target molecules, as they easily conjugate with various detection active substances like antibodies and aptamers. Particularly due to advantages such as low cost, ease of particle synthesis, and high environmental stability compared to enzyme-based colorimetric methods, gold nanoparticles are extensively researched as signal substances in colorimetric assays. This review summarizes various strategies utilizing gold nanoparticles as absorption signal substances, focusing on recent research. Based on the characteristics of gold nanoparticles, where the optical property is influenced by particle morphology, literature is classified and reviewed based on strategies controlling the shape of gold nanoparticles during signal generation. Through this, it is observed that gold nanoparticles, which have been used as absorption signal substances, continue to be actively researched, affirming their potential for broad and continuous improvement in the future.

• Journal of Ecology and Environment
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• v.48 no.1
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• pp.32-48
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• 2024

Background: Longitudinal connectivity in river systems strongly affects biological components related to ecosystem functioning, thereby playing an important role in shaping local biodiversity and ecosystem health. Environmental DNA (eDNA)-based metabarcoding has an advantage of enabling to sensitively diagnose the presence/absence of species, becoming an efficient/effective approach for studying the community structure of ecosystems. However, little attention has been paid to eDNA-based biomonitoring for river systems, particularly for assessing the river longitudinal connectivity. In this study, by using eDNA we analyzed and compared species diversity and composition among artificial barriers to assess the longitudinal connectivity of the fish community along down-, mid- and upstream in the Hotancheon from the Geum River basin. Moreover, we investigated temporal variation in eDNA fish community structure and species diversity according to season. Results: The results of species detected between eDNA and conventional surveys revealed higher sensitivity for eDNA and 61% of species (23/38) detected in both methods. The results showed that eDNA-based fish community structure differs from down-, mid- and upstream, and species diversity decreased from down to upstream regardless of season. We found that there was generally higher species diversity at the study sites in spring (a total number of species across the sites [n] = 29) than in autumn (n = 27). Nonmetric multidimensional scaling and heatmap analyses further suggest that there was a tendency for community clusters to form in the down-, mid- and upstream, and seasonal variation in the community structure also existed for the sites. Dominant species in the Hotancheon was Rhynchocypris oxycephalus (26.07%) regardless of season, and subdominant species was Nipponocypris koreanus (16.50%) in spring and Odontobutis platycephala (15.73%) in autumn. Artificial barriers appeared to negatively affect the connectivity of some fish species of high mobility. Conclusions: This study attempts to establish a biological monitoring system by highlighting the versatility and power of eDNA metabarcoding in monitoring native fish community and further evaluating the longitudinal connectivity of river ecosystems. The results of this study suggest that eDNA can be applied to identify fish community structure and species diversity in river systems, although some shortcomings remain still need to be resolved.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.4
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• pp.86-103
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• 2024

This study interprets the evolving ideologies of Singapore's urban environmental policies focusing on the meanings encapsulated within the notion of 'garden'. Through a comprehensive review of policy documents, legislative materials, development projects, government promotional materials, and organizational changes in each era, the study identifies three phases, each with distinct central themes. Commencing in the 1960s, the initial phase projected a meticulously controlled and managed cityscape using the notion of garden, which was epitomized by the slogan 'Garden City'. In this phase, garden was a representative concept that embodied the cleanliness and greenness of the city, and also served as a strategic rhetoric to effectively transfer the ideology of an exemplary picturesque city to the public. Subsequently, in the 1970s, the focus gradually shifted from individual green spaces and bodies of water towards a collective system which served as a foundational infrastructure of the city-nation. This evolution was reflected in the new slogan 'City in a Garden', where the garden is now not only summoned for its external appearance but also as an unified system which serves as the cornerstone of the city. Through these phases, the Singaporean government developed a scheme capable of integrated management of green spaces and water resources tailored to the scale and function of each. Building upon this foundation, the early 2000s saw the adoption of a new orientation focusing on sustainability and urban ecology, encapsulated in the revised slogan 'City in Nature'. For more than five decades, Singapore has demonstrated an adept utilization of the notion 'garden'. This scholarly examination underscores Singapore's journey in redefining urban landscapes through the strategic employment of the concept of garden in its urban environmental policies. By tracing the evolution of the garden concept across distinct phases, the study illuminates how the Singaporean government leveraged the garden's versatility: from an effective metaphor of aesthetic values to an integral component of its holistic urban system, and finally to a bridge between the urban and the natural.

• Asia pacific journal of information systems
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• v.24 no.3
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• pp.255-279
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• 2014

It is not too much to say that smartphones have become an essential part of our lives due to their versatility. Nevertheless, they still have less overall capabilities than their desktop counterparts. Specifically, they have small screens and low resolutions, which make their applications difficult to have a usable interface. To account for these limitations, the interface of smartphone applications should be designed carefully and properly. Good interface design to any application is critical. However, a comprehensive information systems (IS) literature review found that there has been little research on the user interface design of smartphone applications. More specifically, there has been little empirical evidence and understanding about how metaphors, an imaginative way of describing objects and concepts, in the user interface of smartphone applications affect users' intention to use the applications. Thereby, the research goals of this study are to examine 1) the effects of the metaphors in the user interface of smartphone applications on the interaction between users and applications and 2) the effects of mediating variables including the interaction between users and applications, users' beliefs and attitudes, on users' intention to use the applications. A survey was conducted to collect data. University students and practitioners participated in the survey. A 24-item questionnaire was developed on a 5-point Likert-type scale. The measurement items were mostly adapted from the previous studies in the IS literature and modified to fit the context of this study. First, a principal component factor analysis was performed to explore the inter-relationships among a set of variables. The analysis showed that most of the items loaded quite strongly on the six components. The analysis also revealed the six components with eigenvalues exceeding 1, explaining a total of 70.7 per cent of the variance. The reliabilities of the items were also checked. Most Cronbach alpha values were above 0.8, so the scales were considered reliable. In sum, the results of the analysis support the decision to retain the six factors for further investigation. Next, the structural model was analyzed with AMOS structural equation modeling. The values of GFI, AGFI, NFI, TLI, CFI, and RMSEA were checked. The values showed that the research model considerably have a good fit in general. Next, the convergent and discriminant validities of all constructs were examined. The values for the standardized regression weights and critical ration (CR) indicated sufficient convergent validity for all constructs. In addition, the square root of the average variance extracted (AVE) of each construct was compared with its correlations with all other constructs. The results supported discriminant validity for all constructs. In sum, the results of analysis demonstrated adequate convergent and discriminant validities for all constructs. Finally, path coefficients between the variables were examined. Methphor was found to have an impact on interaction (${\beta}$ = .457, p = .000). There were also significant effects of the interaction on perceived usefulness (${\beta}$ = .273, p = .000) and ease of use (${\beta}$ = .405, p = .000). User attitude was significantly influenced by these two beliefs, perceived usefulness (${\beta}$ = .386, p = .000) and ease of use (${\beta}$ = .347, p = .000) respectively. Further, the results of analysis found that users' intention to use smartphone applications was significantly influenced by user attitude (${\beta}$ = .567, p = .000). Based upon the analyses, all hypotheses were supported. This study found that the metaphors used in the interface of smartphone applications affect not only the interaction between users and applications, but also users' intention to use the applications through the mediating variables, perceived usefulness and ease of use. These findings imply that if the metaphors used in the user interface of application are easy enough to understand for smartphone users, then the application can be perceived useful and easy to use, which in turn make users to have an intention to use the application. In conclusion, this study contributed not only to validate and extend Technology Acceptance Model (TAM) partially, but also to develop the construct of metaphor in smartphone settings. However, since a single empirical study cannot be enough to validate the findings, some limitations should be considered.

• Journal of Intelligence and Information Systems
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• v.18 no.3
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• pp.35-51
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• 2012

Cloud computing is internet-based computing where computing resources are offered over the Internet as scalable and on-demand services. In particular, in case a number of various cloud services emerge in accordance with development of internet and mobile technology, to select and provide services with which service users satisfy is one of the important issues. Most of previous works show the limitation in the degree of user satisfaction because they are based on so called concept similarity in relation to user requirements or are lack of versatility of user preferences. This paper presents cloud service selection reasoning which can be applied to the general cloud service environments including a variety of computing resource services, not limited to web services. In relation to the service environments, there are two kinds of services: atomic service and composite service. An atomic service consists of service attributes which represent the characteristics of service such as functionality, performance, or specification. A composite service can be created by composition of atomic services and other composite services. Therefore, a composite service inherits attributes of component services. On the other hand, the main participants in providing with cloud services are service users, service suppliers, and service operators. Service suppliers can register services autonomously or in accordance with the strategic collaboration with service operators. Service users submit request queries including service name and requirements to the service management system. The service management system consists of a query processor for processing user queries, a registration manager for service registration, and a selection engine for service selection reasoning. In order to enhance the degree of user satisfaction, our reasoning stands on basis of the degree of conformance to user requirements of service attributes in terms of functionality, performance, and specification of service attributes, instead of concept similarity as in ontology-based reasoning. For this we introduce so called a service attribute graph (SAG) which is generated by considering the inclusion relationship among instances of a service attribute from several perspectives like functionality, performance, and specification. Hence, SAG is a directed graph which shows the inclusion relationships among attribute instances. Since the degree of conformance is very close to the inclusion relationship, we can say the acceptability of services depends on the closeness of inclusion relationship among corresponding attribute instances. That is, the high closeness implies the high acceptability because the degree of closeness reflects the degree of conformance among attributes instances. The degree of closeness is proportional to the path length between two vertex in SAG. The shorter path length means more close inclusion relationship than longer path length, which implies the higher degree of conformance. In addition to acceptability, in this paper, other user preferences such as priority for attributes and mandatary options are reflected for the variety of user requirements. Furthermore, to consider various types of attribute like character, number, and boolean also helps to support the variety of user requirements. Finally, according to service value to price cloud services are rated and recommended to users. One of the significances of this paper is the first try to present a graph-based selection reasoning unlike other works, while considering various user preferences in relation with service attributes.

• Journal of Service Research and Studies
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• v.14 no.2
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• pp.48-68
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• 2024

Due to the global pandemic aftermath of the coronavirus, the importance of health care is being emphasized more socially. Due to the influence of these changes, domestic pharmaceutical companies have introduced regular drug delivery services, that is, drug and health functional food subscription services. Currently, this market is continuously growing. However, these regular services are causing new environmental problems in which the number of waste drugs increases due to the presence of unused drugs. Therefore, this study proposes a service that not only promotes health management through regular medication adherence to reduce the amount of pharmaceutical waste but also aims to improve awareness and practices regarding proper medication disposal. As a preliminary survey for service design, a preliminary survey was conducted on 51 adults to confirm their perception of drug use habits and waste drug collection. Based on the Honey Comb model, a guideline for service design was created, and a prototype was produced by specifying the service using the preliminary survey results and service design methodology. In order to verify the effectiveness of the prototype, a first user task survey was conducted to identify the problems of the prototype, and after improving this, a second usability test was conducted on 49 adults to confirm the versatility of the service. Usability verification was conducted using SPSS Mac version 29.0. For the evaluation results of the questionnaire, Spearmann Correlation Analysis was conducted to confirm the relationship between frequency analysis and evaluation items. This study presents specific solutions to the problem of waste drugs due to the spread of drug subscription services.

• MISULJARYO - National Museum of Korea Art Journal
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• v.97
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• pp.87-104
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• 2020

Myogilsang on Diamond Mountain, signed and dated (2000) by Seon-u Yeong (1946-2009), is the first work by a North Korean artist to enter the collection of the National Museum of Korea (fig. 1a). The donor acquired the painting directly from the artist in Pyeongyang in 2006. In consequence, there are no issues with the painting's authenticity.This painting is the largest among all existing Korean paintings, whether contemporary or from the Joseon Dynasty, to depict this iconography (see chart 1. A Chronological List of Korean Myogilsang Paintings.) It is ink and color on paper, measures 130.2 × 56.2 centimeters, and is in a hanging scroll format. Since this essay is intended as a brief introduction of the painting and not in-depth research into it, I will simply examine the following four areas: 1. Seon-u Yeong's background; 2. The location and the traditional appellation of the rock-cut image known as Myogilsang; 3. The iconography of the image; and 4) A comparative analysis of Seon-u Yeong's painting in light of other paintings on the same theme. Finally, I will present two more of his works to broaden the understanding of Seon-u Yeong as a painter. 1. Seon-u Yeong: According to the donor, who met Seon-u at his workshop in the Cheollima Jejakso (Flying Horse Workshop) three years before the artist's death, he was an individual of few words but displayed a firm commitment to art. His preference for subjects such as Korean landscapes rather than motifs of socialist realism such as revolutionary leaders is demonstrated by the fact that, relative to his North Korean contemporaries, he seems to have produced more paintings of the former. In recent years, Seon-u Yeong has been well publicized in Korea through three special exhibitions (2012 through 2019). He graduated from Pyeongyang College of Fine Arts in 1969 and joined the Central Fine Arts Production Workshop focusing on oil painting. In 1973 he entered the Joseon Painting Production Workshop and began creating traditional Korean paintings in ink and color. His paintings are characterized by intense colors and fine details. The fact that his mother was an accomplished embroidery specialist may have influenced on Seon-u's choice to use intense colors in his paintings. By 1992, he had become a painter representing the Democratic People's Republic of Korea with several titles such as Artist of Merit, People's Artist, and more. About 60 of his paintings have been designated as National Treasures of the DPRK. 2. The Myogilsang rock-cut image is located in the Manpok-dong Valley in the inner Geumgangsan Mountain area. It is a high-relief image about 15 meters tall cut into a niche under 40 meters of a rock cliff. It is the largest of all the rock-cut images of the Goryeo period. This image is often known as "Mahayeon Myogilsang," Mahayeon (Mahayana) being the name of a small temple deep in the Manpokdong Valley (See fig. 3a & 3b). On the right side of the image, there is an intaglio inscription of three Chinese characters by the famous scholar-official and calligrapher Yun Sa-guk (1728-1709) reading "妙吉祥"myogilsang (fig. 4a, 4b). 3. The iconography: "Myogilsang" is another name for the Bhodhisattva Mañjuśrī. The Chinese pronunciation of Myogilsang is "miaojixiang," which is similar in pronunciation to Mañjuśrī. Therefore, we can suggest a 妙吉祥 ↔ Mañjuśrī formula for the translation and transliteration of the term. Even though the image was given a traditional name, the mudra presented by the two hands in the image calls for a closer examination. They show the making of a circle by joining the thumb with the ring finger (fig. 6). If the left land pointed downward, this mudra would conventionally be considered "lower class: lower life," one of the nine mudras of the Amitabha. However, in this image the left hand is placed across its abdomen at an almost 90-degree angle to the right hand (fig. 6). This can be interpreted as a combination of the "fear not" and the "preaching" mudras (see note 10, D. Saunders). I was also advised by the noted Buddhist art specialist Professor Kim Jeong-heui (of Won'gwang University) to presume that this is the "preaching" mudra. Therefore, I have tentatively concluded that this Myogilsang is an image of the Shakyamuni offering the preaching mudra. There is no such combination of hand gestures in any other Goryeo-period images. The closest I could identify is the Beopjusa Rock-cut Buddha (fig. 7) from around the same time. 4. Comparative analysis: As seen in , except for the two contemporary paintings, all others on this chart are in ink or ink and light color. Also, none of them included the fact that the image is under a 40-meter cliff. In addition, the Joseon-period paintings all depicted the rock-cut image as if it were a human figure, using soft brushstrokes and rounded forms. None of these paintings accurately rendered the mudra from the image as did Seon-u. Only his painting depicts the natural setting of the image under the cliff along with a realistic rendering of the image. However, by painting the tall cliff in dark green and by eliminating elements on either side of the rock-cut image, the artist was able to create an almost surreal atmosphere surrounding the image. Herein lies the uniqueness of Seon-u Yeong's version. The left side of Seon-u's 2007 work Mount Geumgang (fig. 8) lives up to his reputation as a painter who depicts forms (rocks in this case) in minute detail, but in the right half of the composition it also shows his skill at presenting a sense of space. In contrast, Wave (fig. 9), a work completed one year before his death, displays his faithfulness to the traditions of ink painting. Even based on only three paintings by Seon-u Yeong, it seems possible to assess his versatility in both traditional ink and color mediums.