• Fire Science and Engineering
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• v.31 no.5
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• pp.28-36
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• 2017

In this work, the effects of fire curtain and forced smoke ventilation on smoke spread to auditorium in the stage fire of theater were investigated using the Fire Dynamics Simulator (FDS). For the stage of 31 m (Width)${\times}$34 m (Depth)${\times}$32 m (Height) in dimension, the fast growth fire condition with 10 MW of heat release rate was applied. The forced smoke ventilation was set based on the National Fire Safety Code (NFSC) and previous research. The gap distances between the fire curtain and proscenium wall was established to be 0 m and 0.5 m. When the fire curtain was attached completely to the proscenium wall without any gap, no smoke spread from the stage to the auditorium occurred, independent of forced smoke ventilation. When the gap distance between the fire curtain and proscenium wall was 0.5 m, the smoke layer in the stage descended to the lower height from the bottom than the case without the fire curtain, which was because the smoke spread to auditorium was impeded by the fire curtain. Under the same fire curtain condition, the case with the forced smoke ventilation led to decreasing the mass flow rate of outflow through the gap between the fire curtain and proscenium wall, as compared to the case without the forced smoke ventilation. Based on this study, it was confirmed that the fire curtain and forced smoke ventilation were the effective tools to hold down the smoke spread to the auditorium in the stage fire of theater.

• Fire Science and Engineering
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• v.31 no.5
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• pp.37-43
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• 2017

Domestic sandwich panel buildings are widely used on walls and roofs of factories and warehouse facilities. Factory and warehouse facilities have high fire load and rapid spread of fire due to their use characteristics, leading to large fires. Due to the characteristics of materials, walls and roofs are collapsed, resulting in life damage and property damage. In this regard, this study examined domestic and international standards of sprinkler facilities to prevent ignition of sandwich panel walls. Also, in order to check whether the fire was prevented by installing the head on the wall of the sandwich panel, the fire test was carried out with 10 cm, 60 cm, and 120 cm from the wall along the sprinkler head installation standard of domestic fire safety standards. As a result of the fire test, it was confirmed that the sandwich panel was prevented from igniting when the head of water pressure 0.1 MPa and water quantity K-80 was installed. According to the separation distance, it was impossible to measure the temperature at 10 cm, but at 60 cm, At the maximum temperature of $525^{\circ}C$ and 120 cm, the maximum temperature of the wall of the sandwich panel was measured as $276^{\circ}C$. As a result of the fire test, considering the fire point of 450 degrees Celsius in the fire test of the sandwich panel, the distance from the sandwich panel wall to the combustible is more than 120 cm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.12-20
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• 2016

With the enhancements in existing major industries, cloud computing-based converging services have been created, as well as value-added industries. A variety of converging services are now provided, from personalized services up to industrial services. In Korea, they have become the driving force behind existing industries throughout the whole economy, but mainly in finance, mobile systems, social computing, and home services, based on cloud services. However, not only denial of service (DOS) and distributed DOS (DDOS) attacks have occurred, but also attack techniques targeting core data in storage servers. Even security threats that are hardly detected, such as multiple attacks on a certain target, APT, and backdoor penetration have also occurred. To supplement defenses against these, in this article, a protocol for authority management is designed to provide users with safe storage services. This protocol was studied in cases of integration between a cloud environment and big data-based technology, security threats, and their requirements. Also studied were amalgamation examples and their requirements in technology-based cloud environments and big data. With the protocol suggested, based on this, security was analyzed for attack techniques that occur in the existing cloud environment, as well as big data-based techniques, in order to find improvements in session key development of approximately 55%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.50-57
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• 2017

In the injection molding process, a core that builds a space for a product is installed at the internal place in the mold and fabricated as the frame of the mold. In this make up, the fabricating partial form of the mold at a pin is a core pin. The core pin is finer because an injection mold produces miniaturization and integration. On the other hand, when the core is manufactured using the existing centerless grinder, it generates vibrations because of the lack of a fixed zig for a micro size workpiece. For this reason, an existing centerless grinder without a micron size fixed zig, makes a defective product due to vibration and deformation. In this study, a compact grinding system that can be installed using an existing centerless grinder was fabricated to make a micro size core pin. Using the compact grinding system, grinding experiment for core pin was carried out. The performance of the system was confirmed by measuring the surface roughness, roundness, and cylindricity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.293-303
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• 2017

Thus study examined the possible the link between social enterprises and lifelong education for the underprivileged. To this end, this study searched for the definition and position of social enterprises emerging from the welfare system under the influence of neoliberalism and overcoming the problems in terms of creating social jobs and providing welfare services. In addition, the lifelong education for the underprivileged was examined according to the subjects, such as the disabled, migrant women, young and adult low-income group, and senior citizens. The plan was as follows. First, the expansion of the proportion of community-affiliated social enterprises was analyzed. Second, it provides a differentiated support and protection market for social enterprise. Third, the development and dissemination of social entrepreneur training programs was examined. The results showed that the entire society should have a sense of responsibility for the support of the underprivileged. This provides implications for the linkage of lifelong education and social enterprise in the expansion possibility to improve the quality of life and expand lifelong education for the underprivileged.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.171-179
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• 2009

This paper explores the current situation of the broadcasting program production by video journalists (VJs), one of the recent trends of broadcasting production, centering around the programs made in Daejeon. The result of the survey shows that VJ programs are considered to be one of the generalized broadcasting program production systems. Thus, production costs should be γeadjusted to a realistic level in order to secure the good quality VJ programs in the current situation. Local broadcasting stations should depart from the idea that they make a VJ program subcontract to produce programs at low cost. It is time to support good quality VJ programs financially and systematically. The survey also reveals that most video journalists cannot participate in the decision-making process regarding program production. Local broadcastings should cooperate with video journalists, as co-producers, in producing the programs. Besides, VJ programs have some disadvantages such as limitation of high definition image production, poor image quality, instability of images taken, etc Hence, video journalists should also try to make better image quality of their broadcasting programs. Local subcontractors should make efforts to overcome their poor manpower and production environments as well. By economizing their scale of production and updating their production equipment, subcontractors need to constantly develop the contents related to local community which make them more competitive.

• Korean Journal of Family Social Work
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• no.62
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• pp.103-139
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• 2018

The purpose of this study was to explore the social workers' reflections developed during the participatory action research seeking practice methods in the community welfare center single parent self-help groups. Nine social workers and researchers sharing difficulties in the community welfare center single parent self-help group practice were involved in the participatory action research. We performed a circulatory research repeating 'plan-action-reflection-replan' cycles through ten sessions of research meetings including peer supervision in parallel with 4 self-help group practices. Multiple practice methods were derived as the result among which change in the social workers' perception was the key. We focused on the result that the social workers' perception was changed by reflections from participatory action research and the contents of the reflections were qualitatively analyzed using materials acquired during the study. As a result the following 5 themes were derived; 'recognition and worry on the lack of appropriate practice for the self-help group', 'specification of the social workers' role based on the changed perspective on the member-social worker relation', 'confirmation of the possibility of the concerned person initiated practice', 'detailed understanding of the single parent self-help group in the community welfare center', and 'renewed recognition of the development of the single parent self-help group in the community welfare center'. Based on these results, empowerment and reflection/reflective practice for single parent self-help group in the community welfare center were discussed.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.674-683
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• 2021

Purpose: The purpose of this study is to examine the changes in the pattern of crimes caused by the spread and slowdown of coronavirus infections and to devise preventive and countermeasures against various crimes in the future. Method: In order to find out the characteristics of each crime in the non-face-to-face and face-to-face environment, the results of previous prior research and data officially released by the National Police Agency and the prosecution office were compared and analyzed. Result: In the early epidemic of infectious diseases, overall crime has decreased, and civil life-related crimes and crimes targeting the socially disadvantaged are increasing. In the second half of the infectious disease, unlike the first half, the prolonged corona caused the economic recession and unemployment, deepening the damage from illegal private finance and significantly increasing illegal gambling game crimes. Conclusion: According to the time of the outbreak of the COVID-19 pandemic, the quarterly crime characteristics showed that there was a difference in crime type and crime increase and decrease rate, and that crime response measures should be changed accordingly.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.899-909
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• 2021

In Musculoskeletal ultrasound examination, a linear transducer (12-5 MHz) with a contact surface length of 6 cm, which is commonly distributed in medical institutions, does not contact with bent fingers and wrist depressions only by using a conventional liquid ultrasound gel, which causes image loss. In order to solve this image loss, the use of commercially available Water gel pad is increasing. However, it is a disposable medical product. Repeated use is prohibited and expensive. In this study, in order to reduce the economic burden caused by the use of the commercialized Water gel Pad, we searched for water-soluble food thickener powder that can be easily purchased around our lives and manufactured Gel pads. Among them, kappa-Carrageenan Gel Pad, iota-Carrageenan Gel Pad, and Agar-Agar Gel Pad satisfied the evaluation criteria without artifacts in image evaluation using the N-365 Multipurpose Phantom. Also, the price to purchase the food thickener powder was about 38 times cheaper than the existing commercialized Water gel pad. As a result, if you use the food thickener powder such as kappa-Carrageenan, iota-Carrageenan and Agar-Agar to make solidified elastic Gel pad without a cover instead of the commercially available expensive disposable Water gel pad, the convenience and usefulness of use are improved. It is judged that the manufactured Gel pads can contribute well to the role of efficient ultrasound propagation medium.

• Journal of Digital Forensics
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• v.12 no.3
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• pp.109-120
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• 2018

The smartphone is the communication device that is the most personal to the user, and it keeps a lot of information related to the user and makes information communication with other devices. With these characteristics, forensics on smartphones are one of the most basic methods of investigation in criminal investigations, and have actually contributed to the settlement of the case by providing many clues. However, recently, it is designed to encrypt data stored as a social issue related to the protection of user's personal information, or to delete deleted data or to delete log data together. So, any solutions? In this paper, I try to find the answer from cloud data stored by smartphone user account. Cloud forensics should approach complementary relationships rather than smartphone forensics. There are a lot of data stored in the cloud that can be meaningfully used in the investigation. Online activity information of users, such as Internet usage, YouTube view, and contents purchase information, cloud service such as e-mail, cloud drive, and location information are the most representative data. These data can be unvaluable, but here are some important clues in various types of criminal investigations. In this paper, I propose a method to extract data from the google cloud so that the data can be used for investigation, and to utilize the extracted data for investigation. And it explains the role of the extracted artifacts in the actual investigation business through virtual cases and proves its value.