• Journal of the Korea Society of Computer and Information
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• v.24 no.7
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• pp.135-141
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• 2019

The purpose of this study is to extract the key words from the list of research subjects related to 'hotel workers' published in recent 10 years(2009~2018) by using the language network analysis method and to confirm the relation between the key words. In this paper, we propose a semantic network analysis that can overcome limitations of longitudinal study, analyze the recent research trends, and widely use as a research model. The results of this study are as follows ; First, in analyzing major key words in the title of 'Hotel Employer' in recent 10 years, the major keyword of job satisfaction(40), special grade(26), organizational commitment(20), emotional labor(19), service(12), restaurant(10), and turnover intention(9). Second, we analyzed the relation of language network among major key words extracted from the study title of 'hotel workers'. Such a research process is expected to grasp the trends of research related to 'hotel workers' and give implications for the future direction of related research.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.153.3-153
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• 2001

Recently, the researches on the mobile computing technologies for palm computers, PDA´s and wearable computers became very active. In the development of mobile devices, one of the key technologies is the human interface. So, this paper suggests a new input device for PDA´s and wearable computers so-called key-glove. The design methods of key-glove are discussed in this paper and we manufactured the key-glove which recognizes that character is typed in though the hand´s movements analysis and is designed as an input device for wearable computers and virtual environment. Also, we are executes a performance test for alphanumeric data entry, command entry and X-Y pointer input. In the results, we are confirmed in its ...

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.340-344
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• 2009

Multi-server password authentication schemes enable remote users to obtain service from multiple servers with single password without separately registering to each server. In 2007, Hu-Niu-Yang proposed an improved efficient password authenticated key agreement scheme for multi-server architecture based on Chang-Lee's scheme proposed in 2004. This scheme is claimed to be more efficient and is able to overcome a few existing deficiencies in Chang-Lee's scheme. However, we find false claim of forward secrecy property and some potential threats such as offline dictionary attack, key-compromise attack, and poor reparability in their scheme. In this paper, we will discuss these issues in depth.

• ETRI Journal
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• v.38 no.1
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• pp.52-61
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• 2016

A microblog is a service typically offered by online social networks, such as Twitter and Facebook. From the perspective of information dissemination, we define the concept behind a spreading matrix. A new WeiboRank algorithm for identification of key nodes in microblog networks is proposed, taking into account parameters such as a user's direct appeal, a user's influence region, and a user's global influence power. To investigate how measures for ranking influential users in a network correlate, we compare the relative influence ranks of the top 20 microblog users of a university network. The proposed algorithm is compared with other algorithms - PageRank, Betweeness Centrality, Closeness Centrality, Out-degree - using a new tweets propagation model - the Ignorants-Spreaders-Rejecters model. Comparison results show that key nodes obtained from the WeiboRank algorithm have a wider transmission range and better influence.

• Journal of the Ergonomics Society of Korea
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• v.36 no.4
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• pp.267-280
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• 2017

Objective: The aim of this study is to investigate key user experience factors of interactions for Head Mounted Display (HMD) devices in the Virtual Reality Environment (VRE). Background: Virtual reality interaction research has been conducted steadily, while interaction methods and virtual reality devices have improved. Recently, all of the virtual reality devices are head mounted display based ones. Also, HMD-based interaction types include Remote Controller, Head Tracking, and Hand Gesture. However, there is few study on usability evaluation of virtual reality. Especially, the usability of HMD-based virtual reality was not investigated. Therefore, it is necessary to study the usability of HMD-based virtual reality. Method: HMD-based VR devices released recently have only three interaction types, 'Remote Controller', 'Head Tracking', and 'Hand Gesture'. We search 113 types of research to check the user experience factors or evaluation scales by interaction type. Finally, the key user experience factors or relevant evaluation scales are summarized considering the frequency used in the studies. Results: There are various key user experience factors by each interaction type. First, Remote controller's key user experience factors are 'Ease of learning', 'Ease of use', 'Satisfaction', 'Effectiveness', and 'Efficiency'. Also, Head tracking's key user experience factors are 'Sickness', 'Immersion', 'Intuitiveness', 'Stress', 'Fatigue', and 'Ease of learning'. Finally, Hand gesture's key user experience factors are 'Ease of learning', 'Ease of use', 'Feedback', 'Consistent', 'Simple', 'Natural', 'Efficiency', 'Responsiveness', 'Usefulness', 'Intuitiveness', and 'Adaptability'. Conclusion: We identified key user experience factors for each interaction type through literature review. However, we did not consider objective measures because each study adopted different performance factors. Application: The results of this study can be used when evaluating HMD-based interactions in virtual reality in terms of usability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.410-415
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• 2013

Recently, as Internet enters WEB 2.0, many social network services through such as Facebook, Twitter and Youtube appeared. In these social network sites, users can easily make friends, join groups and access others personal information. Therefore, a malicious user can easily gather information of others. In order to protect user's personal information from the unauthenticated users, we propose privacy protection mechanism based on key assignment and user's trust level. A master-key is generated for each users and is segmented into a core-key and several sub-key. The master-key stores at the information owner's side and the sub-key will be distributed to requestor according to the relation and trust level. At last, in order to proof the efficiency, the performance of our proposed mechanism is compared with those of existing mechanisms.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.92-103
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• 2021

Lactobacillus casei, one of the most widely used probiotics, has been reported to alleviate multiple diseases. However, the effects of this species on intestinal diseases are strain-specific. Here, we aimed to screen L. casei strains with inflammatory bowel disease (IBD)-alleviating effects based on in vitro physiological characteristics. Therefore, the physiological characteristics of 29 L. casei strains were determined, including gastrointestinal transit tolerance, oligosaccharide fermentation, HT-29 cell adhesion, generation time, exopolysaccharide production, acetic acid production, and conjugated linoleic acid synthesis. The effects of five candidate strains on mice with induced colitis were also evaluated. The results showed that among all tested L. casei strains, only Lactobacillus casei M2S01 effectively relieved colitis. This strain recovered body weight, restored disease activity index score, and promoted anti-inflammatory cytokine expression. Gut microbiota sequencing showed that L. casei M2S01 restored a healthy gut microbiome composition. The western blotting showed that the alleviating effects of L. casei M2S01 on IBD were related to the inhibition of the NF-κB pathway. A good gastrointestinal tolerance ability may be one of the prerequisites for the IBD-alleviating effects of L. casei. Our results verified the efficacy of L. casei in alleviating IBD and lay the foundation for the rapid screening of L. casei strain with IBD-alleviating effects.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1749-1752
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• 2012

Colorectal cancer (CRC), now the third most common cancer across the world, is known to aggregate in families. USP7 is a very important protein with an important role in regulating the p53 pathway, which is critical for genomic stability and tumor suppression. We here genotyped eight SNPs within the USP7 gene and conducted a case-control study in 312 CRC patients and 270 healthy subjects in the Chinese Han population. No significant associations were found for any single SNP and CRC risk. Our data eliminate USP7 as a potential candidate gene towards for CRC in the Han Chinese population.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.831-839
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• 2023

Tylosin is a potent veterinary macrolide antibiotic produced by the fermentation of Streptomyces fradiae; however, it is necessary to modify S. fradiae strains to improve tylosin production. In this study, we established a high-throughput, 24-well plate screening method for identifying S. fradiae strains that produce increased yields of tylosin. Additionally, we constructed mutant libraries of S. fradiae via ultraviolet (UV) irradiation and/or sodium nitrite mutagenesis. A primary screening of the libraries in 24-well plates and UV spectrophotometry identified S. fradiae mutants producing increased yields of tylosin. Mutants with tylosin yield 10% higher than the wild-type strain were inoculated into shake flasks, and the tylosin concentrations produced were determined by high-performance liquid chromatography (HPLC). Joint (UV irradiation and sodium nitrite) mutagenesis resulted in higher yields of mutants with enhanced tylosin production. Finally, 10 mutants showing higher tylosin yield were re-screened in shake flasks. The yield of tylosin A by strains UN-C183 (6767.64 ± 82.43 ㎍/ml) and UN-C137 (6889.72 ± 70.25 ㎍/ml) was significantly higher than that of the wild-type strain (6617.99 ± 22.67 ㎍/ml). These mutant strains will form the basis for further strain breeding in tylosin production.

• Journal of Arbitration Studies
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• v.9 no.1
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• pp.367-390
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• 1999

The basic requirements for conducting electronic commerce include confidentiality, integrity, authentication and authorization. Cryptographic algorithms, make possible use of powerful authentication and encryption methods. Cryptographic techniques offer essential types of services for electronic commerce : authentication, non-repudiation. The oldest form of key-based cryptography is called secret-key or symmetric encryption. Public-key systems offer some advantages. The public key pair can be rapidly distributed. We don't have to send a copy of your public key to all the respondents. Fast cryptographic algorithms for generating message digests are known as one-way hash function. In order to use public-key cryptography, we need to generate a public key and a private key. We could use e-mail to send public key to all the correspondents. A better, trusted way of distributing public keys is to use a certification authority. A certification authority will accept our public key, along with some proof of identity, and serve as a repository of digital certificates. The digital certificate acts like an electronic driver's license. The Korea government is trying to set up the Public Key Infrastructure for certificate authorities. Both governments and the international business community must involve archiving keys with trusted third parties within a key management infrastructure. The archived keys would be managed, secured by governments under due process of law and strict accountability. It is important that all the nations continue efforts to develop an escrowed key in frastructure based on voluntary use and international standards and agreements.