• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.5
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• pp.1450-1470
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• 2023

In a Vehicular Cloud (VC) network, an announcement protocol plays a critical role in promoting safety and efficiency by enabling vehicles to disseminate safety-related messages. The reliability of message exchange is essential for improving traffic safety and road conditions. However, verifying the message authenticity could lead to the potential compromise of vehicle privacy, presenting a significant security challenge in the VC network. In contrast, if any misbehavior occurs, the accountable vehicle must be identifiable and removed from the network to ensure public safety. Addressing this conflict between message reliability and privacy requires a secure protocol that satisfies accountability properties while preserving user privacy. This paper presents a novel announcement protocol for secure communication in VC networks that utilizes group signature to achieve seemingly contradictory goals of reliability, privacy, and accountability. We have developed the first comprehensive announcement protocol for VC using group signature, which has been shown to improve the performance efficiency and feasibility of the VC network through performance analysis and simulation results.

• Journal of Conservation Science
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• v.28 no.1
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• pp.75-86
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• 2012

Iksan Mireuksaji Stone pagoda was built A.D. 639 when King Moo was governing Baekje, in which Sarira has been enshrined in a hole dug in the stereobate for 1,370 years. In South Korea, about 150 cases of Sarira have been found so far. In this connection, many studies have been conducted on how to manage it and on its genesis, but there have been no data on environments to which it has been exposed. In this study, accordingly, researches were made into environments to which Sarira has been exposed as well as into how much it has been damaged under the environments. Sarira in wooden pagodas was influenced greatly by water, but that in stone pagodas by saturated relative humidity. Thus, Sarira in the containers was significantly influenced by the outside temperature for 1 to 2 days, but had no any reaction to humidity. The time it took for the humidity in a Sarira container to reach its maximum, varied depending upon the humidity of the day when Sarira was enshrined. In the case of this pagoda, the humidity reached its maximum 30 days later.

• Journal of Korean Neurosurgical Society
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• v.61 no.6
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• pp.680-688
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• 2018

Objective : To mitigate the risk of iatrogenic instability, new posterior decompression techniques able to preserve musculoskeletal structures have been introduced but never extensively investigated from a biomechanical point of view. This study was aimed to investigate the impact on spinal flexibility caused by a unilateral laminotomy for bilateral decompression, in comparison to the intact condition and a laminectomy with preservation of a bony bridge at the vertebral arch. Secondary aims were to investigate the biomechanical effects of two-level decompression and the quantification of the restoration of stability after posterior fixation. Methods : A universal spine tester was used to measure the flexibility of six L2-L5 human spine specimens in intact conditions and after decompression and fixation surgeries. An incremental damage protocol was applied : 1) unilateral laminotomy for bilateral decompression at L3-L4; 2) on three specimens, the unilateral laminotomy was extended to L4-L5; 3) laminectomy with preservation of a bony bridge at the vertebral arch (at L3-L4 in the first three specimens and at L4-L5 in the rest); and 4) pedicle screw fixation at the involved levels. Results : Unilateral laminotomy for bilateral decompression had a minor influence on the lumbar flexibility. In flexion-extension, the median range of motion increased by 8%. The bone-preserving laminectomy did not cause major changes in spinal flexibility. Two-level decompression approximately induced a twofold destabilization compared to the single-level treatment, with greater effect on the lower level. Posterior fixation reduced the flexibility to values lower than in the intact conditions in all cases. Conclusion : In vitro testing of human lumbar specimens revealed that unilateral laminotomy for bilateral decompression and bone-preserving laminectomy induced a minor destabilization at the operated level. In absence of other pathological factors (e.g., clinical instability, spondylolisthesis), both techniques appear to be safe from a biomechanical point of view.

• Food Science and Preservation
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• v.14 no.5
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• pp.474-480
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• 2007

Response surface methodology (RSM) was employed to optimize extraction conditions preserving valuable functional properties of fluid Cheonggukjang obtained from red ginseng. Based on a central composite design, the study plan was established using variations in microwave power, ethanol concentration, and extraction time. Regression analysis was applied to obtain a mathematical model. A maximum electron donating ability (EDA) of 99.09% was obtained under the specific extraction conditions of microwave power 135.62 W, ratio of solvent to sample contents. 3.60 g/mL, and an extraction time of 11.79 min. The maximum inhibitory effect on tyrosinase activity was 10.02% at 119.16 W, 4.02 g/mL, and 5.57 min. The maximum superoxide dismutase (SOD)-like activity was 63.83% under the extraction conditions of 125.29 W, 4.04 g/mL, and 11.02 min. Based on superposition of four-dimensional RSM data obtained to optimize electron donating ability, nitrite-scavenging ability, inhibitory effect on tyrosinase activity, and SOD-like activity, the optimum ranges of extraction conditions were found to be a microwave power of $l{\sim}85 W$, a ratio of solvent to sample content of $1.4{\sim}2.8\;g/mL$, and an extraction time of $6.5{\sim}11\;min$.

• Journal of the Korean Society of Safety
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• v.7 no.4
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• pp.101-104
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• 1992

It is shown that for a characteristic equation of continuous linear system, stability can be determined by conditions srggested in this paper. And also It Is of interest to Know how much coefficients of the low-order characteristic equation(N$\leq$5) can be perturbed while simutanously preserving the stable condition of the equation. This result is analogous to result by Anderson et al. based on the Kharitonov's conditions and Hermite - Biehler theorem.

• Proceedings of the Safety Management and Science Conference
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• 2013.04a
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• pp.485-500
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• 2013

Cultural assets of the country's history and cherish the living conditions of the people, conscious and cohesive crystals, and the pride of the hearts of the people as a haven. In the country worth preserving national treasure, bomulgeup, local cultural heritage as a major cultural property protection are. Cultural properties, etc. Most are wooden, is vulnerable to fire, and, moreover battling to far away from the city and due to the geographical conditions are very challenging aspects. The national cultural assets, such as the many temples, vows to fire one if the loss of a centuries-old cultural property is a big loss of national posterity to great shame is not. Still cultural assets and a large number of visitors have flocked temples. All of us to keep the look and feel of the cultural assets pleasure to conserve cultural assets preserved to ensure that fire prevention is always unmistakably bear in mind that sees.

• Carbon letters
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• v.11 no.2
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• pp.96-101
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• 2010

Dispersion of the functionalized multiwalled nanotubes (MWNT) in the polyurethane (PU) matrix and DC conductivity of the MWNT/PU composites are investigated with the oxidation conditions, the kind of surfactants and their content. First, the most optimal surfactant type and its critical micelle concentration in the MWNT suspension are determined as a cationic surfactant, benzalkonium chloride (BKC) of 0.6 wt.% to the MWNT content from DEA and FESEM results. All the MWNT oxidized under several conditions are negatively charged and functionalized with carboxylic group, whereas the degree of damage is different from oxidation conditions. In addition, each MWNT/PU composite derived from several oxidation conditions shows different DC conductivity at a characteristic MWNT content. It is found that in order to enhance DC conductivity of the polymeric composites containing the oxidized MWNT the better dispersion of MWNT should be obtained by effective functionalities and surfactant adsorption with preserving the intrinsic geometry of pristine MWNT.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.3892-3901
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• 2021

The pressure drop of a moisture separator in a steam generator is the important design parameter to ensure the successful performance of a nuclear power plant. The moisture separators have a wide range of operating conditions based on the arrangement of them. The prediction of the pressure drop in a moisture separator is challenging due to the complexity of the multi-dimensional two-phase vortex flow. In this study, the moisture separator test facility using the air/water two-phase flow was used to predict the pressure drop of a moisture separator in a Korean OPR-1000 reactor. The prototypical steam/water two-phase flow conditions in a steam generator were simulated as air/water two-phase flow conditions by preserving the centrifugal force and vapor quality. A series of experiments were carried out to investigate the effect of hydraulic characteristics such as the quality and liquid mass flux on the two-phase pressure drop. A new prediction model based on the scaling law was suggested and validated experimentally using the full and half scale of separators. The suggested prediction model showed good agreement with the steam/water experimental results, and it can be extended to predict the steam/water two-phase pressure drop for moisture separators.

• Journal of Ecology and Environment
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• v.48 no.2
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• pp.128-136
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• 2024

Background: Prasiola japonica is a freshwater green algae species that can only be seen in Korea and Japan. The various conditions necessary for its growth and reproduction have not been fully elucidated. Therefore, in this study, we aimed to investigate conditions related to the growth and reproduction of P. japonica for the purpose of conserving and producing this species. We first examined differences in growth according to various conditions in different habitats to understand the growth environment of P. japonica. Results: The experimental results revealed that the optimal temperature for growth and reproduction of P. japonica was between 10℃-15℃, and the optimal light intensity was 1,000-1,500 lux. Furthermore, when Provasoli enriched seawater with iodine (PESI) agar was used, the growth of P. japonica was found to be at least 1.5-8 times greater than that of the general Sohan Valley water sample, and it also showed 2-4.5 faster growth rate to reach 30 ㎛. These results emphasize the importance of PESI agar in the culture of P. japonica, and are expected to be helpful in suggesting ways to utilize and conserve P. japonica resources. Conclusions: Through these research findings, we suggest new methods for conserving and producing P. japonica, highlight the importance of preserving the P. japonica ecosystem, and explore ways to utilize P. japonica resources. This research promotes the understanding and protection of P. japonica resources in Korea and beyond, and underscores the need for further research and conservation efforts.

• Korean Journal of Heritage: History & Science
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• v.49 no.1
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• pp.146-165
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• 2016

With the introduction of the system of recognizing masters of craft and performance skills in 1970, the principle of "preserving the original form," which was already in general use, was adopted as a legal principle in the Cultural Heritage Protection Act. While the concept "original form" can be related to tangible elements of heritage through the Act, the intangibility of craft and performance skills does not allow their pinpointing at a particular temporal period or the identification of a particular master from the past as the basis of an original form. Therefore, those craft or performance skills that are available at the point of recognition of relevant masters must serve as the basis of the original form for the intangible heritage concerned. This means that the principle of preserving the original form of intangible heritage has been implemented not based on a fundamental form of materiality, but rather on the craft or performance skills that may be held by a master at the time of his/her recognition as a "temporary original form." This principle has been observed through intangible heritage transmission and education policies for recognized masters and their trainees, contributing to establish an elitist transmission environment in which public were denied to join the education on intangible heritage. Even with policies guided by the principle of preserving the original form, designated craft and performance skills have been transformed contingent upon given social and environmental conditions, thus hindering the preservation of the original form. Despite the intrinsic limitations of the principle of preserving the original form when applied to intangible heritage, this principle has served as a practical guideline for protecting traditional Korean culture from external influences such as modernization and Westernization, and also as an ultimate goal for the safeguarding of intangible heritage, engendering actual policy effects. The Act on the Safeguarding and Promotion of Intangible Cultural Heritage that comes into effect in March 2016 takes the constantly evolving nature of intangible heritage into consideration and resultantly adopts a concept of "essential form" (jeonhyeong) in place of "original form" (wonhyeong). This new concept allows for any transformations that may take place in the environment surrounding the intangible heritage concerned, and is intended to mitigate the rigidity of the concept of "original form." However, it should be noted that "essential form," which is manifested as the unique significance, knowledge, and skills delivered by the intangible heritage concerned, should be maintained according to the guidelines and principles related to heritage conservation. Therefore, the new concept can be understood not as a rupture, but more as a continuum of the concept of "original form."