• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3365-3383
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• 2021

The rapid growth of data has successfully promoted the development of modern information and communication technologies, which are used to process data generated by public urban departments and citizens in modern cities. In specific application areas where the ciphertext of messages generated by different users' needs to be transmitted, the concept of broadcast encryption is important. It can not only improve the transmission efficiency but also reduce the cost. However, the existing schemes cannot entirely ensure the privacy of receivers and dynamically adjust the user authorization. To mitigate these deficiencies, we propose an efficient, secure identity-based broadcast encryption scheme that achieves direct revocation and receiver anonymity, along with the analysis of smart grid solutions. Moreover, we constructed a security model to ensure wireless data transmission under cloud computing and internet of things integrated devices. The achieved results reveal that the proposed scheme is semantically secure in the random oracle model. The performance of the proposed scheme is evaluated through theoretical analysis and numerical experiments.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.1
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• pp.74-81
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• 2021

UAM(Urban Air Mobility) systems have evolved in the form of helicopters in the 1960~1970s, tiltrotors in the 1980s, small aircraft transportation systems in the 2000s, and electric-powered Vertical Take-Off and Landing (eVTOL) in the 2010s; accordingly, the early heliport has evolved to its current form of a Vertiport. Vertical Takeoff and Landing Sites, Vertiports, are important factors for the successful introduction of UAM, along with the resolution of air traffic control (ATC), air security, and noise problems. However, there are no domestic or international installation standards and guidelines yet. Therefore, in this study, installation standards were prepared by referring to domestic and international case studies, ICAO standards, and MIT research papers. The study proposes to establish standards for Final Approach and Takeoff Area (FATO) as 1.5D, 1D for Touchdown and Lift-Off Area (TLOF), and 1.5D for Safety Area (SA). It also proposes to add "UAM Vertiport Installation Standards" to the 「Act on the Promotion and Foundation of Drone Utilization, Drone Act」.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.283-292
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• 2022

Advanced radiation applications have been widely used and extended to many fields. As a result of this fact, choosing an appropriate shielding material based on the radiation application has become vital. In this regard, the integration of elements into polymer composites has been investigated and contributed to the quantity and quality of radiation shielding materials. This study reports photon attenuation parameters and electromagnetic shielding effectiveness of a novel polymer composite prepared with a matrix reinforced with three different proportions (5, 10, and 15 wt%) of niobium content. Addition of Nb dopant improves both photon attenuation and electromagnetic shielding effectiveness for the investigated composites. Therefore, Nb(15%) polymer composite with highest concentration has been found to be the best absorber for ionizing and non-ionizing radiations. Consequently, the performed analyzes provide evidences that the prepared Nb-reinforced polymer composite could be effectively used as photon radiation attenuator and electromagnetic shielding material.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.77-84
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• 2022

The purpose of this study is to derive implications by comparing the spatial distribution of each service facility per unit population(1,000 people) with population decline areas. For this purpose, major concepts such as living infrastructure services, Spatial Distribution of Rural Living Service Facilities, areas of declining population, and regional extinction were reviewed and trends in prior research. Based on the literature review, 'Spatial Distribution of Rural Living Service Facilities' analysis criteria were set, and it was derived by 'the number of facilities per 1,000 population by township' using population data and rural space data. And the trend of each service sector was identified and implications were derived with 89 cities and counties in 'depopulation areas' suggested by the Ministry of Public Administration and Security. The derived implications are as follows. In the medical, leisure, and sports infrastructure sectors, 'rural areas with few service facilities per unit population' and 'depopulated areas' tended to coincide. In addition, the distribution characteristics of rural and urban areas differed by sector, which is judged to depend on the inclusion of rural facilities and population density.

• Earthquakes and Structures
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• v.25 no.5
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• pp.325-342
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• 2023

The damping modification factor (DMF) is used to modify the 5%-damped response spectrum to produce spectral values that correspond to other necessary damping ratios for seismic design. The DMF has been the subject of numerous studies, and it has been discovered that seismological parameters like magnitude and distance can have an impact on it. However, DMF formulations incorporating these seismological parameters cannot be directly applied to seismic design because these parameters are not specified in the present seismic codes. The goal of this study is to develop a formulation for the DMF that can be directly applied in seismic design and that takes the effects of magnitude, distance, and site conditions into account. To achieve this goal, 16660 ground motions with magnitudes ranging from 4 to 9 and epicentral distances ranging from 10 to 200 km are used to systematically study the effects of magnitude, distance, and site conditions on the DMF. Furthermore, according to the knowledge that magnitude and distance affect the DMF primarily by changing the spectral shape, a spectral shape factor is adopted to reflect influences of magnitude and distance, and a new formulation for the DMF incorporating the spectral shape factor is developed. In comparison to the current formulations, the proposed formulation provides a more accurate prediction of the DMF and can be employed directly in seismic design.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.903-921
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• 2024

Industry 5.0 puts forward higher requirements for smart cities, including low-carbon, sustainable, and people-oriented, which pose challenges to the design of smart cities. In response to the above challenges, this study introduces the cyber-physical-social system (CPSS) and parallel system theory into the design of smart cities, and constructs a smart city framework based on parallel system theory. On this basis, in order to enhance the security of smart cities, a sustainable patrol subsystem for smart cities has been established. The intelligent patrol system uses a drone platform, and the trajectory planning of the drone is a key problem that needs to be solved. Therefore, a mathematical model was established that considers various objectives, including minimizing carbon emissions, minimizing noise impact, and maximizing coverage area, while also taking into account the flight performance constraints of drones. In addition, an improved metaheuristic algorithm based on ant colony optimization (ACO) algorithm was designed for trajectory planning of patrol drones. Finally, a digital environmental map was established based on real urban scenes and simulation experiments were conducted. The results show that compared with the other three metaheuristic algorithms, the algorithm designed in this study has the best performance.

• Research in Community and Public Health Nursing
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• v.16 no.2
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• pp.137-147
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• 2005

Purpose: This study was conducted to investigate physical health status. depression. activities of daily living (ADL & IADL) of the low-income elderly who live alone in urban areas. Method: The subjects were the 400 low-income elders who live alone in Daegu city and the following instruments were used: 1. The number of self-reported physical health problems and present diseases: 2. CES-D scale for depression by Jo Nam-Oak et al. (1998): and 3. ADL scale by Katz (1989) and IADL scale by Lawton and Brody (1969). Results: 1. Visual difficulty was the most prevailing problem (55.3%) among physical problems. the second bowel elimination and the third hearing disturbance. As for present diseases. arthritis (26.5%), hypertension(24.3%) and DM (11.8%) were the most common diseases. 2. There were significant differences in physical health status according to age (t=3.115. p=.045). kind of medical security (t=-1.973. p=.049). perceived life satisfaction (F=4.966. p=.007) and the number of present diseases (F=2.937. p=.033). 3. There were significant differences in depression according to sex (t=-3.758. p=.000) . kind of medical security (t=-4.368. p=.000). perceived life satisfaction (F=35.743. p=.000) and the number of present diseases (F=4.246. p=.006). 4. There were significant differences in ADL according to sex (t=-2.136. p=.033) and age (F=4.863. p=.008). and in IADL according to sex (t=4.552, p=.000), age (F=3.090. p=.047) and kind of medical security (t=-3.306. p=.001). 5. Physical health state was correlated positively with both the number of present diseases (r=.140. p=.005) and depression (r=.352. p=.000), and negatively with ADL (r=-.176. p= .000) and IADL (r= -.230. p=.000). Depression was correlated positively with the number of present diseases (r=.169. p=.001) and negatively with both ADL (r=-.139. p=.005) and IADL (r=-.203. p= .000). Conclusion: The results of this study suggest that general characteristics are important factors for physical health status, depression. ADL and IADL of the low-income elderly who live alone and there are close relations among physical health status, the number of diseases, depression, ADL and IADL. Therefore, these results must be reflected in community health programs for the low-income elderly who live alone. In addition, this kind of study must be extended to the low-income elderly who live alone in rural areas.

• Korean Security Journal
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• no.18
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• pp.1-20
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• 2009

Nowadays most nations around the world including Korea have experienced absolute shortages of available urban space. To solve various problems of the city, each nation constantly tends to extend the underground space. However there is a serious problem in making use of the underground space. Especially new terrorism coming into existence after 9.11 terror turns into the so-called ‘soft target’ which has something to do with public transportation facilities available to most people. Good examples are like these: poisonous gas attacks in Tokyo subway in 1995, Daegu subway station fire in 2003, serial bomb blast of London subway in 2005. In spite of being a concern on incidents related to the underground space it is inevitable to utilize the underground space and the tendency is growing. But Korea lags badly behind in foreign countries in this field and so seeking measures is urgently needed. Therefore the aim of this study is to note visible damages stemmed from the domestic and foreign underground space and propose more effective and adequate measures. Safety measures of terrorism are associated to minimize damage out of terrorism and they are as follows. In the first place, preparing protective equipment for saving a life from fire attacks and poisonous gas is needed urgently. In the second place, counterpart management on the spot and systematic security training should be established in order to minimize injury. In the third place, fire escapes must be provided for a rapid evacuation of potential unspecified individuals. In the fourth place, building up a network of related institutions is required for a systematic omnidirectional counterpart. Finally the Korean government ought to take fast and appropriate actions for the injured and bereaved family of the terror incident.

• Korean Security Journal
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• no.55
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• pp.117-141
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• 2018

Police crime statistics report that residential housing such as apartment, low rise, detached houses is the second most vulnerable to crime, which is closely followed by the number of street crimes. Also residential houses are often exposed to quality-of-life crime, e.g burglary. It threatens the basic human rights of house residents in terms of safety and comfort within the urban living environment. This study examines related precedent studies regarding the vulnerability of residential housing including studios, multi-family housing from the viewpoint of crime prevention through environment design(CPTED), extracted the elements and items suitable for the safety of residential facilities and the certification evaluation indicators and check items to be the basis for the checklist are derived. Based on these evaluation indicators and inspection items, we conducted on-site surveys of residential facilities in three areas of Seoul, Yongin and Asan, and the final draft of the checklist was revised based on the results of the field survey. There are 43 items on the 7 fields of evaluation in the final version of checklist, 11 items in the management and operation, 20 items in the surveillance, 7 items in the access control, 1 item in the territoriality, 2 items in the activity support, and 2 items in the security and safety facilities. In addition, various points of interest were added to allow the administrator of the residential facility to earn points for special measures taken for safety. This checklist can be appropriately modified and utilized in consideration of the characteristics of each facility. Korean national police agency has CPOs to check the residential facilities in their jurisdiction using checklists and to certify excellent facilities with high level of safety.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.213-221
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• 2018

South Korea has been reluctant to open its geospatial information overseas to ensure security as a divided country. However, this cannot continue as the domestic and international environments related to geospatial information and the industrial ecosystem of information and communication technologies have been changing dramatically. Within this context, this study aims to analyze the causal relations among relevant variables and how they change and interact with time using a systems thinking process. First, causal maps were created for the domains of national security, map-based convergence service, and corporate competition. Then, the causal maps for each domain were integrated, based on which the points for policy intervention and dominant feedback loops were identified. The analysis results showed that securing the self-sufficiency of domestic geospatial businesses is a key element to determine the whole causal map, and the variable that changes the dominant feedback loop from a vicious circle to a virtuous one is the decision to open geospatial information overseas. In this study, I found the policy leverage that is a policy intervention point that can produce a great effect with little input by building a causal map of the interactions between major variables. This study is significant in that it identified and analyzed the dominant feedback loop as to which causal structure would dominate the system in the long term. The results of this study can be used to discuss not only the impacts of map data overseas opening on the national security and geospatial information industry, but also the interactions in the future when Google or other global companies request to release the geospatial information.