• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.499-505
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• 2022

Recently, the metaverse has been receiving a lot of attention. Metaverse means a virtual space, and various events can be held in this space. In particular, 360-degree video, a format optimized for the metaverse space, is attracting attention. A 360-degree video image is created by stitching images taken with multiple cameras or lenses in all 360-degree directions. When shooting a 360-degree video, a variety of shooting equipment, including a shooting staff to take a picture of a subject in front of the camera, is displayed on the video. Therefore, when shooting a 360-degree video, you have to hide everything except the subject around the camera. There are several problems with this shooting method. Among them, lighting is the biggest problem. This is because it is very difficult to install a fixture that focuses on the subject from behind the camera as in conventional image shooting. This study is an experimental study to find the optimal angle for 360-degree images by adjusting the angle of indoor lighting. We propose a method to record 360-degree video without installing additional lighting. Based on the results of this study, it is expected that experiments will be conducted through more various shooting angles in the future, and furthermore, it is expected that it will be helpful when using 360-degree images in the metaverse space.

• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.99-113
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• 2021

In these days, as cyberspace has been recognized as the fifth battlefield area following the land, sea, air, and space, attention has been focused on activities that view cyberspace as an operational and mission domain in earnest. Also, in the 21st century, cyber operations based on cyberspace are being developed as a 4th generation warfare method. In such an environment, the success of the operation is determined by the commander's decision. Therefore, in order to increase the rationality and objectivity of such decision-making, it is necessary to systematically establish and select a course of action (COA). In this study, COA is established by using the method of classifying operational elements necessary for cyber operation, and it is intended to suggest a direction for quantitative evaluation of COA. To this end, we propose a method of composing the COES (Cyber Operational Elements Set), which becomes the COA of operation, and classifying the cyber operational elements identified in the target development process based on the 5W1H Method. In addition, by applying the proposed classification method to the cyber operation elements used in the STUXNET attack case, the COES is formed to establish the attack COAs. Finally, after prioritizing the established COA, quantitative evaluation of the policy was performed to select the optimal COA.

• Journal of Korea Port Economic Association
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• v.39 no.1
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• pp.115-129
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• 2023

This study analyzed the risk spillover of BDI on shipping company stock prices through the Copula-CoVaR method based on daily data from January 4, 2010, to October 31, 2022. The main empirical analysis results and policy implications are as follows. First, copula results showed that there was a weak dependence between BDI and shipping company stock prices, and PAN, KOR, and YEN were selected as the most fitting model for dynamic Student-t copula, HMM was selected as the rotated Gumbel copula, and KSS was selected as the best model. Second, in the results of CoVaR, it was confirmed that the upside (downside) CoVaR was significantly different from the upside (downside) VaR in all shipping companies. This means that BDI has a significant risk spillover on shipping companies. In addition, as for the risk spillover, the downside risk is generally lower than the upside risk, so the downside and upside risk spillover were found to be asymmetrical. Therefore, policymakers should strengthen external risk supervision and establish differentiated policies suitable for domestic conditions to prevent systematic risks from BDI shocks. And investors should reflect external risks from BDI fluctuations in their investment decisions and construct optimal investment portfolios to avoid risks. On the other hand, investors propose that the investment portfolio should be adjusted in consideration of the asymmetric characteristics of up and down risks when making investment decisions.

• Journal of Korean Academy of Nursing
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• v.53 no.4
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• pp.468-479
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• 2023

Purpose: This study aimed to evaluate the use of the respiratory rate oxygenation (ROX) index, ROX-heart rate (ROX-HR) index, and saturation of percutaneous oxygen/fraction of inspired oxygen ratio (SF ratio) to predict weaning from high-flow nasal cannula (HFNC) in patients with respiratory distress in a pediatric intensive care unit. Methods: A total of 107 children admitted to the pediatric intensive care unit were enrolled in the study between January 1, 2017, and December 31, 2021. Data on clinical and personal information, ROX index, ROX-HR index, and SF ratio were collected from nursing records. The data were analyzed using an independent t-test, χ² test, Mann-Whitney U test, and area under the curve (AUC). Results: Seventy-five (70.1%) patients were successfully weaned from HFNC, while 32 (29.9%) failed. Considering specificity and sensitivity, the optimal cut off points for predicting treatment success and failure of HFNC oxygen therapy were 6.88 and 10.16 (ROX index), 5.23 and 8.61 (ROX-HR index), and 198.75 and 353.15 (SF ratio), respectively. The measurement of time showed that the most significant AUC was 1 hour before HFNC interruption. Conclusion: The ROX index, ROX-HR index, and SF ratio appear to be promising tools for the early prediction of treatment success or failure in patients initiated on HFNC for acute hypoxemic respiratory failure. Nurses caring for critically ill pediatric patients should closely observe and periodically check their breathing patterns. It is important to continuously monitor three indexes to ensure that ventilation assistance therapy is started at the right time.

• Journal of the Korea Institute of Building Construction
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• v.23 no.5
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• pp.607-618
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• 2023

Pervasive research underscores the direct correlation between an enhanced safety climate and a marked reduction in accidents. The intricacies of safety climate are governed by three pivotal strata: organizational management, on-site operations, and the broader enterprise framework. Within an organizational context, sustaining optimal performance across these layers poses a considerable challenge, often attributable to the constraints of available managerial bandwidth. It becomes imperative, then, to conceive a phased enhancement blueprint for the safety climate. To orchestrate this blueprint with precision, a discerning understanding of the hierarchy of safety climate metrics is essential, which subsequently guides judicious managerial resource allocation. This investigation is anchored in elucidating the hierarchical significance of safety climate metrics through the Analytical Hierarchy Process(AHP). Implementing the AHP framework, both a questionnaire was disseminated and a subsequent analysis undertaken, culminating in the extraction of relative priorities of safety climate determinants. Consequent to this analysis, "workers' safety prioritization and risk aversion" emerged as the foremost dimension, holding a significance weight of 0.1900. Furthermore, within the detailed elements, "unwavering adherence to safety mandates amidst demanding operational constraints" ranked supreme, manifesting a weight of 0.6663. The findings encapsulated in this study are poised to be foundational in sculpting improvements at an institutional level and devising policies, all with the end goal of fostering an exemplar safety climate within construction arenas.

• The Transactions of the Korea Information Processing Society
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• v.13 no.2
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• pp.48-59
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• 2024

As functions that support virtualization on their own in hardware are developed, user applications having various workloads are operating efficiently in the virtualization system. SR-IOV is a virtualization support function that takes direct access to PCI devices, thus giving a high I/O performance by minimizing the need for hypervisor or operating system interventions. With SR-IOV, network I/O acceleration can be realized in virtualization systems that have relatively long I/O paths compared to bare-metal systems and frequent context switches between the user area and kernel area. To take performance advantages of SR-IOV, network resource management policies that can derive optimal network performance when SR-IOV is applied to an instance such as a virtual machine(VM) or container are being actively studied.This paper evaluates and analyzes the network performance of SR-IOV implementing I/O acceleration is compared with Virtio in terms of 1) network delay, 2) network throughput, 3) network fairness, 4) performance interference, and 5) multi-network. The contributions of this paper are as follows. First, the network I/O process of Virtio and SR-IOV was clearly explained in the virtualization system, and second, the evaluation results of the network performance of Virtio and SR-IOV were analyzed based on various performance metrics. Third, the system overhead and the possibility of optimization for the SR-IOV network in a virtualization system with high VM density were experimentally confirmed. The experimental results and analysis of the paper are expected to be referenced in the network resource management policy for virtualization systems that operate network-intensive services such as smart factories, connected cars, deep learning inference models, and crowdsourcing.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.189-203
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• 2008

The physical and chemical properties of radioactive waste drums, which have been temporarily stored on site, should be characterized before their shipment to a disposal facility in order to prove that the properties meet the acceptance guideline. The investigation of NDT(Nondestructive Test) method was figured out that the contents in drum, the quantitative analysis of free standing water and void fraction can be examined with X-ray NDT techniques. This paper describes the characteristics of X-ray NDT such as its principles, the considerations for selection of X-ray system, etc. And then, the waste drum characteristics such as drum type and dimension, contents in drum, etc. were examined, which are necessary to estimate the optimal X-ray energy for NDT of a drum. The estimation results were that: $(R)\acute{A}$ the proper X-ray energy is under 3 MeV to test the drums of 320 ${\beta}\S$ and less; $(R)\ddot{E}$ both X-ray systems of 450 keV and/or 3 MeV might be needed considering the economical efficiency and the realization. The number of drums that can be tested with 450 keV and 3 MeV X-ray system was figured out as 42,327 and 18,105 drums (based on storage of 2006. 12), respectively. Four testing scenarios were derived considering equipment procurement method, outsourcing or not, etc. The economical and feasibility assessment for the scenarios was resulted in that an optimal scenario is dependent on the acceptance guide line, the waste generator's policy on the waste treatment and the delivery to a disposal facility, etc. For example, it might be desirable that a waste generator purchases two 450 keV mobile system to examine the drums containing low density waste, and that outsourcing examination for the high density drums, if all NDT items such as quantitative analysis for 'free standing water' and 'void fraction', and confirmation of contents in drum have to be characterized. However, one 450 keV mobile system seems to be required to test only the contents in 13,000 drums per year.

• Journal of the Korean association of regional geographers
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• v.2 no.1
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• pp.69-85
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• 1996

This research adoptes a spatial analysis function of the Geographic Information System[GIS] to analyze the location and the service district of a collective consumption facility, to discover the optimal location, and to redefine the service district. The location and spatial district of a collective consumption facility strongly influences the quality of life of residents. This research studies administrative offices and districts, especially Gu-offices in Ulsan. Ulsan would be raised to the status of Kwangyokshi in 1997; so that, the status of four Gus would be changed from a general administration into a self-governing administration. The summary of this research focuses on five significant points. First, the districts of four Gus were strongly required to be redefined to obtain the maximization of the degree of potential development as well as of the efficiency and equity of administring services. The spatial range of residents in a Gu was not in accord with its administrative district. The administrative districts of four Gus in Ulsan were not balanced in terms of area and population, and the high degree of disparity among Gus existed the efficiency and equality of a collective consumption service. Second, the current gu-offices were located based on security of land and accessibility of a main route; so, there was difficult to find the creteria and the principles of selections of the location of Gu offices. The social disparity of an administrative service existed in the accessibility into Gu-offices. Third, the administrative districts of Gus were redefined with spatial analysis tool of ARC/INFO. It was recommended that Ulsan maintain four Gus under the condition of five Kwangyokshi in South Korea. The redefined districts of administration reduced the disparity among four Gus in terms of area and population. improved the degree of harmony between the spatial range of residents of Gus and the administrative district of Gus, and increased the efficiency and equity of administrative service. Fourth, within the redefined adminis trative district of a Gu, the centroid reduced the maximum distance and mean distance; so, the efficiency and equity of public service provided by the Gu-office were improved. Last, the spatial analysis function of GIS helped to select the optimal location and to delineate the district of public service with more speedly and objectively. The function of spatial analysis of GIS was very useful to minimize the conflict in the determination of the location of a collective consumption facility and of the service district. To improve location analysis with GIS. non-spatial data base such as budget, thought of residents, and development policy and program, should be constructed.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.363-369
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• 2018

One of the recent environmental problems is climate change due to the increase of atmospheric $CO_2$, which causes ecological changes and various environmental problems. Therefore, various studies are being carried out to reduce $CO_2$ in the world in order to solve various environmental problems caused by increase of $CO_2$. The $CO_2$ reduction using microalgae is an environmentally friendly method by using photosynthesis reaction of microalgae. However, most studies using single species. There is no study on the $CO_2$ fixing efficiency of microalgae in natural rivers. Therefore, this study was to identify the microalgae in the Sum river and to analyze the growth characteristics of microalgae in the river to obtain optimal culture conditions. And the changes of biomass and chlorophyll-a of microalgae were analyzed according to $CO_2$ concentration and injection rate. The purpose of this study was to investigate the fixing efficiency of carbon dioxide in microalgae in natural rivers. Six kinds of dominant species were observed as a result of the identification of microalgae in Sum river(Ankistrodesmus falcatus, Scenedesmus intermedius, Selenodictyum sp., Xanthidium apiculatum var. laeve, Cosmarium pseudoquinarium, Dictyosphaerium pulchellum). All of these species were green algae. Biomass and chlorophyll-a increased with the increase of $CO_2$ concentration and biomass and chlorophyll-a increased faster flow rate at the same $CO_2$ concentration. Also, the quantity of $CO_2$ fixation on the microalgae tended to be higher when the flow rate of injected gas was faster. This study can be referred as being significant in the micro-algae in river. In addition, the optimal conditions for $CO_2$ fixation of microalgae in rivers and the quantification of the quantity of $CO_2$ fixation from microalgae in rivers can be used as basic data for future policy of $CO_2$ reduction.

• Journal of the Korean Society for Library and Information Science
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• v.4
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• pp.43-71
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• 1975

Operations research has developed rapidly since its origins in World War II. Practitioners of O. R. have contributed to almost every aspect of government and business. More recently, a number of operations researchers have turned their attention to library and information systems, and the author believes that significant research has resulted. It is the purpose of this essay to introduce the library audience to some of these accomplishments, to present some of the author's hypotheses on the subject of library management to which he belives O. R. has great potential, and to suggest some future research directions. Some problem areas in librianship where O. R. may play a part have been discussed and are summarized below. (1) Library location. It is usually necessary to make balance between accessibility and cost In location problems. Many mathematical methods are available for identifying the optimal locations once the balance between these two criteria has been decided. The major difficulties lie in relating cost to size and in taking future change into account when discriminating possible solutions. (2) Planning new facilities. Standard approaches to using mathematical models for simple investment decisions are well established. If the problem is one of choosing the most economical way of achieving a certain objective, one may compare th althenatives by using one of the discounted cash flow techniques. In other situations it may be necessary to use of cost-benefit approach. (3) Allocating library resources. In order to allocate the resources to best advantage the librarian needs to know how the effectiveness of the services he offers depends on the way he puts his resources. The O. R. approach to the problems is to construct a model representing effectiveness as a mathematical function of levels of different inputs(e.g., numbers of people in different jobs, acquisitions of different types, physical resources). (4) Long term planning. Resource allocation problems are generally concerned with up to one and a half years ahead. The longer term certainly offers both greater freedom of action and greater uncertainty. Thus it is difficult to generalize about long term planning problems. In other fields, however, O. R. has made a significant contribution to long range planning and it is likely to have one to make in librarianship as well. (5) Public relations. It is generally accepted that actual and potential users are too ignorant both of the range of library services provided and of how to make use of them. How should services be brought to the attention of potential users? The answer seems to lie in obtaining empirical evidence by controlled experiments in which a group of libraries participated. (6) Acquisition policy. In comparing alternative policies for acquisition of materials one needs to know the implications of each service which depends on the stock. Second is the relative importance to be ascribed to each service for each class of user. By reducing the level of the first, formal models will allow the librarian to concentrate his attention upon the value judgements which will be necessary for the second. (7) Loan policy. The approach to choosing between loan policies is much the same as the previous approach. (8) Manpower planning. For large library systems one should consider constructing models which will permit the skills necessary in the future with predictions of the skills that will be available, so as to allow informed decisions. (9) Management information system for libraries. A great deal of data can be available in libraries as a by-product of all recording activities. It is particularly tempting when procedures are computerized to make summary statistics available as a management information system. The values of information to particular decisions that may have to be taken future is best assessed in terms of a model of the relevant problem. (10) Management gaming. One of the most common uses of a management game is as a means of developing staff's to take decisions. The value of such exercises depends upon the validity of the computerized model. If the model were sufficiently simple to take the form of a mathematical equation, decision-makers would probably able to learn adequately from a graph. More complex situations require simulation models. (11) Diagnostics tools. Libraries are sufficiently complex systems that it would be useful to have available simple means of telling whether performance could be regarded as satisfactory which, if it could not, would also provide pointers to what was wrong. (12) Data banks. It would appear to be worth considering establishing a bank for certain types of data. It certain items on questionnaires were to take a standard form, a greater pool of data would de available for various analysis. (13) Effectiveness measures. The meaning of a library performance measure is not readily interpreted. Each measure must itself be assessed in relation to the corresponding measures for earlier periods of time and a standard measure that may be a corresponding measure in another library, the 'norm', the 'best practice', or user expectations.