• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.10
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• pp.1994-2005
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• 2015

Voice over IP (VoIP) is a technology for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks. Instead of being transmitted over a circuit-switched network, however, the digital information is packetized, and transmission occurs in the form of IP packets over a packet-switched network which consist of several layers of computers. VoIP Service that used the various techniques has many advantages such as a voice Service, multimedia and additional service with cheap cost and so on. But the various frauds arises using VoIP because VoIP has the existing vulnerabilities at the Internet and based on complex technologies, which in turn, involve different components, protocols, and interfaces. According to research results, during in 2012, 46 % of fraud calls being made in VoIP. The revenue loss is considerable by fraud call. Among we will analyze for Toll Bypass Fraud by the SIM Box that occurs mainly on the international call, and propose the measures that can detect. Typically, proposed solutions to detect Toll Bypass fraud used DPI(Deep Packet Inspection) based on a variety of detection methods that using the Signature or statistical information, but Fraudster has used a number of countermeasures to avoid it as well. Particularly a Fraudster used countermeasure that encrypt VoIP Call Setup/Termination of SIP Signal or voice and both. This paper proposes the solution that is identifying equipment of Toll Bypass fraud using those countermeasures. Through feature of Voice traffic analysis, to detect involved equipment, and those behavior analysis to identifying SIM Box or Service Sever of VoIP Service Providers.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.799-804
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• 2016

Broadband powerline communication (BPLC) uses distribution lines as a medium for achieving effective bidirectional data communication along with electric current flow. As the material characteristics of power lines are not good at the communication channel, the development of power line communication (PLC) systems for internet, voice, and data services requires measurement-based models of the transfer characteristics of the network suitable for performance analysis by simulation. In this paper, an analytic model describing a complex transfer function is presented to obtain the attenuation and path parameters for a multipath power line model. The calculated results demonstrated frequency-selective fading in multipath channels and signal attenuation with frequency, and were in good agreement with the experimental results. Inductive coupling units are used as couplers for coupling the signal to the power line to avoid physical connections to the distribution line. The inductance of the ferrite core, which depends on the frequency, determines the cut-off frequency of the inductive coupler. Coupling loss can be minimized by increasing the number of windings around the coupler. Coupling efficiency was improved by more than 6 dB with three windings compared to the results obtained with one winding.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.5
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• pp.606-611
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• 2009

Performance test was carried out between selective media which are generally used in Staphylococcus aureus isolation from food. Sensitivity, determined according to the appearance of characteristic colonies when 30 different S. aureus strains were tested, resulted as Baird-Parker agar (RPF)> $Petrifilm^{TM}$ Staph Express plate> Baird-Parker agar> Mannitol salt agar. Also, the four different media showed the same selectivity because all tested media did not produce the false positive colonies. Recovery efficiency from the artificially inoculated foodstuff was almost the same for the tested media. Presumptive colonies were collected from the dried fishery product using Mannitol salt agar and collected strains were tested on 4 different selective agar. Almost presumptive strains did not show the false positive colonies except for S. carnosus ssp carnosus. This strain was identified as false positive colonies on Mannitol salt agar, Baird-Parker agar and $Petrifilm^{TM}$ Staph Express plate. But Baird-Parker agar (RPF) did not show the false positive colonies with the same strains. So, it was concluded that the Baird-Parker agar (RPF) has more higher selectivity than other tested media in this experiment.

• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.317-324
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• 1994

This paper proposed a new method in the implementation of ISDN (integrated services digital network) LAPD (link access procedure on the D-channel) and LAPB (link access procedure on the B-channel) protocols. The proposed method in this paper implement ISDW LAPD protocol through multi-tasking operating system and adopt a kernel part that is changed operating system to target board. The features of implemented system are (1) the para.llel processing of the events generated at each layer, as follows (2) the supporting necessary timers for the implementation of ISDW LAPD protocol from the kernel part by using software, (3) the recommanded SAP (Service Access Point) from CCITT was composed by using port function in the operating system. With the proposed method, the protocols of ISDH layerl, layer2 and layer3 (call control) were implemented by using the kernel part and related tests were carried out by connecting the ISDH terminal simulator to ISDN S-interface system using the ISDN LAPD protocol The results showed that ISDW S-interface terminals could be discriminated by TEI (Terminal Equipment Identifier) assignment in layer 2 (LAPD) and the message transmission of layer 3 was verified by establishing the multi-frame transmission and then through the path established by the LAPD protocol, a user data was tranfered and received on B-channel with LAPB protocol Thererfore, as new efficient ISDN S-interface environment was implemented in the thesis, it was verified that the implemented system can be utilized by connecting ISDW in the future to transfer a medical image data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.163-172
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• 2007

The web as global network includes text document, video, sound, etc and connects each distributed information using link Through development of web, it accumulates abundant information and the main is text based documents. Most of user use the web to retrieve information what they want. So, numerous researches have progressed to retrieve the text documents using the many methods, such as probability, statistics, vector similarity, Bayesian, and so on. These researches however, could not consider both the subject and the semantics of documents. As a result user have to find by their hand again. Especially, it is more hard to find the korean document because the researches of korean document classification is insufficient. So, to overcome the previous problems, we propose the korean document classification method for semantic retrieval. This method firstly, extracts TF value and RV value of concepts that is included in document, and maps into U-WIN that is korean vocabulary dictionary to select the topic of document. This method is possible to classify the document semantically and showed the efficiency through experiment.

• Journal of Broadcast Engineering
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• v.24 no.1
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• pp.48-57
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• 2019

The purpose of this study is to understand the intention of the inquirer from the single text type question in Goal-oriented dialogue. Goal-Oriented Dialogue system means a dialogue system that satisfies the user's specific needs via text or voice. The intention analysis process is a step of analysing the user's intention of inquiry prior to the answer generation, and has a great influence on the performance of the entire Goal-Oriented Dialogue system. The proposed model was used for a daily chemical products domain and Korean text data related to the domain was used. The analysis is divided into a speech-act which means independent on a specific field concept-sequence and which means depend on a specific field. We propose a classification method using the word embedding model and the CNN as a method for analyzing speech-act and concept-sequence. The semantic information of the word is abstracted through the word embedding model, and concept-sequence and speech-act classification are performed through the CNN based on the semantic information of the abstract word.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.3
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• pp.257-265
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• 2021

The COVID-19 virus is a β-genus virus that causes infection by mediating the angiotensin convertible enzyme 2 (ACE2) receptor, which is distributed in large numbers in the human respiratory tract. The disease requires effective post-management of antibody production by complete healers and vaccinators because there is no perfect remedy for the virus infection. This study aimed to develop recombinant proteins specifically responsive to neutralizing antibodies in clinical specimens and use them to develop a rapid diagnostic kit to diagnose neutralizing antibodies quickly and conveniently against the COVID-19 virus and confirm the possibility of commercialization through a performance evaluation. Rapid diagnostic kits using COVID-19 S1 RBD recombinant proteins can be applied to rapid diagnostic kits, with positive percentage agreement (PPA) and negative percentage agreement (NPA) of 100% and 98.3%, respectively, compared to the U.S. FDA-approved ELISA kits. If the performance of the rapid diagnostic kit is improved and neutralizing antibodies can be analyzed quantitatively using quantitative analysis equipment, it can be used as important data to predict immunity to the COVID-19 virus and determine additional vaccinations.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.282-289
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• 2019

Gastritis is an inflammatory disease involving the stomach and is caused by several factors, including stress, non-steroidal anti-inflammatory drugs such as aspirin, liquor, and Helicobacter pylori. In Korea, Leonurus japonicus Houttuyn (LJW) has been used as traditional medicine for vaginal bleeding, hematuria, and bruise. Previous studies have reported that LJW exhibited hepatoprotective, cardioprotective, and anti-hyperlipidemic effect. However, the effect of the water extract of LJW on gastritis was not elucidated. Thus, we evaluated the anti-gastric effect and genotoxicity of LJW. LJW effectively prevented the degeneration of surface mucous cells and glandular epithelial cells and vascular congestion induced by HCl/EtOH. Micronucleus assay indicated that the rate of micronucleated polychromatic erythrocytes/polychromatic erythrocytes was not significantly different compared that of the control. Further experiments are required to determine the role of LJW in the gastric injury process such as cyclooxygenase signaling pathway and the secretion of mucus in the stomach.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.203-209
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• 2021

In this study, a prototype design model was proposed for developing an online recruitment system through multi-dimensional data crawling and social media analysis, and validates text information and video interview in job application process. This study includes a comparative analysis process through text mining to verify the authenticity of job application paperwork and to effectively hire and allocate workers based on the potential job capability. Based on the prototype system, we conducted performance tests and analyzed the result for key performance indicators such as text mining accuracy and interview STT(speech to text) function recognition rate. If commercialized based on design specifications and prototype development results derived from this study, it may be expected to be utilized as the intelligent online recruitment system technology required in the public and private recruitment markets in the future.

• Journal of the Korea Computer Graphics Society
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• v.30 no.1
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• pp.1-10
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• 2024

In immersive virtual environments including mixed reality (MR) and virtual reality (VR), avatars or agents, which are virtual humans, are being studied and applied in various ways as factors that increase users' social presence. Recently, studies are being conducted to apply generative AI as an agent to improve user learning effects or suggest a collaborative environment in an immersive virtual environment. This study proposes a novel method for interface application of a virtual assistant agent (VAA) using OpenAI's ChatGPT in an immersive virtual environment including VR and MR. The proposed method consists of an information agent that responds to user queries and a control agent that controls virtual objects and environments according to user needs. We set up a development environment that integrates the Unity 3D engine, OpenAI, and packages and development tools for user participation in MR and VR. Additionally, we set up a workflow that leads from voice input to the creation of a question query to an answer query, or a control request query to a control script. Based on this, MR and VR experience environments were produced, and experiments to confirm the performance of VAA were divided into response time of information agent and accuracy of control agent. It was confirmed that the interface application of the proposed VAA can increase efficiency in simple and repetitive tasks along with user-friendly features. We present a novel direction for the interface application of an immersive virtual environment through the proposed VAA and clarify the discovered problems and limitations so far.