• ETRI Journal
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• v.43 no.3
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• pp.561-570
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• 2021

This paper presents master key identifier based protocol steganography (MKIPS), a new approach toward creating a covert channel within the Secure Real-time Transfer Protocol, also known as SRTP. This can be achieved using the ability of the sender of Voice-over-Internet Protocol packets to select a master key from a pre-shared list of available cryptographic keys. This list is handed to the SRTP sender and receiver by an external key management protocol during session initiation. In this work, by intelligent utilization of the master key identifier field in the SRTP packet creation process, a covert channel is created. The proposed covert channel can reach a relatively high transfer rate, and its capacity may vary based on the underlying SRTP channel properties. In comparison to existing data embedding methods in SRTP, MKIPS can convey a secret message without adding to the traffic overhead of the channel and packet loss in the destination. Additionally, the proposed covert channel is as robust as its underlying user datagram protocol channel.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.39-39
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• 2023

Nonlinear weirs, such as labyrinth and piano key weirs, are suitable methods to handle increased flood flows that may be expected due to climate change. Although specific physical models are considered to be an effective way of investigating fluid flows, simply conducting physical model tests is insufficient to fully comprehend the hydraulic and discharge characteristics of non-linear weirs. In this study, computational fluid dynamics algorithms have been used extensively to investigate complex flow physics instead of relying on reduced scale models. The discharge capacity of the piano key weir and the rectangular labyrinth weir is compared using a three-dimensional numerical model, which is validated by the available experimental data. The results confirm that piano key weir is more efficient than the rectangular labyrinth weir for a wide range of head water ratios. By analyzing the contribution of discharge over inlet, outlet and sidewall crests, the factor that make the piano key weir superior to the rectangular weir is the sidewall discharge.

• International Journal of Highway Engineering
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• v.16 no.3
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• pp.9-20
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• 2014

PURPOSES : This study is to compare load transfer efficiency of key joint and dowel joint for airport concrete pavement. METHODS : As AC150/5320-6D of FAA's [Advisory Circular] was changed into AC150/5320-6E, Key joint type of rigid pavement were excluded from Construction Joints. LTE(Load Transfer Efficiency) of dowel joint and key joint were compared by times and seasons through pavement temperature measurement, ocular investigation and HWD measurement. RESULTS : For the joint performance grade of No. 2(The second) runway of airport, 12% of poor rate was observed in key joint and 2% of poor rate in dowel joint. Poor rate of key joint was increased to 17%, if only No. 3~No. 6 slabs, which are mostly loaded from the airplanes, were applied for the study. In apron area, LTE poor rate of key joint was high in winter, and LTE poor rate of dowel joint was at least above 'Fair' grade. In summer, 'Fair' for key joint, 'Acceptable' for dowel joint appeared. CONCLUSIONS : As results, dowel joint was superior than key joint for LTE. Deviations of seasons and times were smaller in dowel joint's result. And LTE in winter was lower than LTE in summer.

• The Journal of Society for e-Business Studies
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• v.12 no.4
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• pp.17-27
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• 2007

This paper proposes a key distribution and authentication protocol between user, service provider and key distribution center (KDC). This protocol is based on symmetric cryptosystem, challenge-response, Diffie-Hellman component and hash function. In the proposed protocol, user and server update the session key under token-update operation, and user can process repeated efficient authentications by using updated session keys. And another merit is that KDC needs not to totally control the session key between user and server in proposed protocol. Even an attacker steals the parameters from the KDC, the attacker still can not calculate session key. According to the comparison and analysis with other protocols, our proposed protocol provides good efficiency and forward secure session key.

• Human Ecology Research
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• v.57 no.1
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• pp.127-142
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• 2019

This study investigates factors that impact dating relationship stability(DRS) among college students by applying two key concepts from the Interdependence Theory suggested by Kelly & Thibaut (1978; Thibaut & Kelly, 1959), the comparison level(CL) and comparison level for alternatives($CL_{alt}$). This study also examined mediating effects of commitment on the relationship between CL and DRS and $CL_{alt}$ and DRS. The research used a survey data set drawn from 327 college students currently involved in a dating relationship. The collected data set was then analyzed using SPSS software ver. 23.0 and AMOS software ver. 25.0, to produce the descriptive statistics, Pearson's correlations, and path analysis with bootstrapping. First, both CL and $CL_{alt}$ had a significant direct impact on DRS. In terms of effect size, CL's effect size was comparatively larger than $CL{_{alt}}'s$. The mediating effects from the commitment were evidenced. In the model, the commitment partially mediated the relationships between CL and DRS, and $CL_{alt}$ and DRS. The findings suggest that commitment still plays a key role in dating relationships among college students who currently have a romantic partner. The findings of this study show the possibilities in applying the concepts and theory of interdependence to explain current dating relationships among young adults.

• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.35-47
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• 2006

In an Ubiquitous Environment, the growth of various services and equipment is forecasted to increase both the multicast users and diverse hacking attacks of the multicast key. Rapid increasing of multicast users and application security protocols reduce the performance of the Central key management system. Accordingly. We propose to elevate the functionality of the key management mechanism for greater efficiency and stability of the multicast services. in this paper The existing key management mechanism comparison and simulation will analyze these problems. We propose the advanced SMKD (Secure Multicast Key Distribution) mechanism application of the small group and key length control new security protocol by methods to solve these problems. The SMKD Model in this paper will help reduce loading the key distribution and encryption execution of a central key management system, and this model can also ensure stability to a central key management system by efficient key management.

• The Korean Journal of Food & Health Convergence
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• v.6 no.3
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• pp.1-4
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• 2020

This study analyzed in nutrient contents changes of adult's favorite foods between March 2019 and July 2020 after policy implementation nutrient-poor foods based on special act on safety control of adult's dietary life in Korea. Among adult's favorite foods manufactured or sold in 2020 as well as 2019, calories and key nutrients in breads, ice creams and pizzas were improved in comparison to those in the other food groups. However, most of the changes in calories or key nutrient contents exist. The newly introduced candies, breads showed slightly greater improvements in calories and key nutrient contents than in 2019. On the other hand, some negative changes were found in newly introduced chocolates in comparison to previous ones. Overall, policy implementation on foods seemed to induce changes in nutrient contents of adult's favorite foods. In particular, nutrition education is reported to have a positive impact on adult's frequency and preference for processed foods, and more systematic and continuous nutrition education measures should be devised to help adult as consumers selectively purchase healthy foods. This research is meaningful in that it is the first study to analyze the quality changes of adult's favorite foods since the high-calorie and low-nutrient food management policy.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7187-7193
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• 2014

Background: The aim of this meta-analysis was to compare sensitivities and specificities of fine needle aspiration (FNA) and core needle biopsy (CNB) in the diagnosis of thyroid cancer. Materials and Methods: Articles were screened in Medline, the Cochrane Library, EMBASE and Google Scholar, and subsequently included and excluded based on the patient/problem-intervention-comparison-outcome (PICO) principle. Primary outcome was defined in terms of diagnostic values (sensitivity and specificity) of FNA and CNB for thyroid cancer. Secondary outcome was defined as the accuracy of diagnosis. Compiled FNA and CNB results from the final studies selected as appropriate for meta-analysis were compared with cases for which final pathology diagnoses were available. Statistical analyses were performed for FNA and CNB for all of the selected studies together, and for individual studies using the leave-one-out approach. Results: Article selection and screening yielded five studies for meta-analysis, two of which were prospective and the other three retrospective, for a total of 1,264 patients. Pooled diagnostic sensitivities of FNA and CNB methods were 0.68 and 0.83, respectively, with specificities of 0.93 and 0.94. The areas under the summary ROC curves were 0.905 (${\pm}0.030$) for FNA and 0.745 (${\pm}0.095$) for CNB, with no significant difference between the two. No one study had greater influence than any other on the pooled estimates for diagnostic sensitivity and specificity. Conclusions: FNA and CNB do not differ significantly in sensitivity and specificity for diagnosis of thyroid cancer.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.74-83
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• 2008

In animation films, the movements of characters are exaggerated and comical. Traditional key-frame animation techniques allow to control exaggeration and comicality of characters at animators' wills. But, recently introduced motion capture techniques have limits on representing comicality and exaggeration although it is convenient to capture subjects' natural looks. This paper chooses two animations from key-frame and motion capture techniques and looks into comicality and exaggeration of characters by analyzing movements and motion of them Movements are classified as four fundamental motion elements - running, jump, gesture and walking - and are analyzed to compare the way of representation from two films. By studying similarity and differentiation of movements of two films, this paper discusses the advantages and disadvantages of key-frame and motion capture techniques in terms of exaggeration and comicality. Comparison of the character movements from two techniques shows that there are common differentiations of those movements.

• Mycobiology
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• v.51 no.1
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• pp.36-48
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• 2023

Xanthoria elegans is a lichen symbiosis, that inhabits extreme environments and can absorb UV-B. We reported the de novo sequencing and assembly of X. elegans genome. The whole genome was approximately 44.63 Mb, with a GC content of 40.69%. Genome assembly generated 207 scaffolds with an N50 length of 563,100 bp, N90 length of 122,672 bp. The genome comprised 9,581 genes, some encoded enzymes involved in the secondary metabolism such as terpene, polyketides. To further understand the UV-B absorbing and adaptability to extreme environments mechanisms of X. elegans, we searched the secondary metabolites genes and gene-cluster from the genome using genome-mining and bioinformatics analysis. The results revealed that 7 NR-PKSs, 12 HR-PKSs and 2 hybrid PKS-PKSs from X. elegans were isolated, they belong to Type I PKS (T1PKS) according to the domain architecture; phylogenetic analysis and BGCs comparison linked the putative products to two NR-PKSs and three HR-PKSs, the putative products of two NR-PKSs were emodin xanthrone (most likely parietin) and mycophelonic acid, the putative products of three HR-PKSs were soppilines, (+)-asperlin and macrolactone brefeldin A, respectively. 5 PKSs from X. elegans build a correlation between the SMs carbon skeleton and PKS genes based on the domain architecture, phylogenetic and BGC comparison. Although the function of 16 PKSs remains unclear, the findings emphasize that the genes from X. elegans represent an unexploited source of novel polyketide and utilization of lichen gene resources.