• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.11-20
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• 2020

As the manufacturing environment becomes more complex, traditional simulation models alone are having a lot of difficulties in reflecting real-time manufacturing situations. Although the Digital Twin concept is actively discussed as an alternative to overcome theses issues, many studies are being carried out only in the product design phase. This research presents a Digital Twin-based manufacturing environment framework for applying the Digital Twin concept to the manufacturing process. Twin model that is operated in virtual space, physical system and databases describing the actual manufacturing environment, are proposed as detailed components that make up the framework. To check the applicability of proposed framework, a simple Digital Twin-based manufacturing system was simulated in a conveyor system using Arena software and Excel VBA. Experiment results have shown that the twin model is transmitted real time data from the physical system via DB and were operating in the same time unit. The Excel VBA fitted parameters defined by cycle time based on historical data that real-time and training data are being accumulated together. This study proposes operating method of digital twin model through the simple experiment examples. The results lead to the applicability of Digital twin model.

• Journal of Intelligence and Information Systems
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• v.29 no.1
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• pp.41-63
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• 2023

As the online e-commerce market growing, the need for a recommender system that can provide suitable products or services to customer is emerging. Recently, many studies using the sentiment score of online review have been proposed to improve the limitations of study on recommender systems that utilize only quantitative information. However, this methodology has limitation in extracting specific preference information related to customer within online reviews, making it difficult to improve recommendation performance. To address the limitation of previous studies, this study proposes a novel recommendation methodology that applies deep learning technique and uses various linguistic factors within online reviews to elaborately learn customer preferences. First, the interaction was learned nonlinearly using deep learning technique for the purpose to extract complex interactions between customer and product. And to effectively utilize online review, cognitive contents, affective contents, and linguistic style matching that have an important influence on customer's purchasing decisions among linguistic factors were used. To verify the proposed methodology, an experiment was conducted using online review data in Amazon.com, and the experimental results confirmed the superiority of the proposed model. This study contributed to the theoretical and methodological aspects of recommender system study by proposing a methodology that effectively utilizes characteristics of customer's preferences in online reviews.

• Journal of Korea Foundry Society
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• v.43 no.6
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• pp.302-309
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• 2023

In general, castings often have complex shapes and significant variations in thickness within a single product, making grid generation for simulations challenging. Casting flows involve multiphase flows, requiring the tracking of the boundary between air and molten metal. Additionally, considerable time is spent calculating pressure fields due to density differences in a numerical analysis. For these reasons, the Cartesian grid system has traditionally been used in mold filling simulations. However, orthogonal grids fail to represent shapes accurately, leading to a momentum loss caused by the stair-like grid patterns on curved and sloped surfaces. This can alter the flow of molten metals and result in incorrect casting process designs. To address this issue, simulations in the Cartesian grid system involve creating a large number of grids to represent shapes more accurately. Alternatively, the Cut Cell method can be applied to address the problems arising from the Cartesian grid system. In this study, analysis results based on the number of grid in the Cartesian grid system for a casting flow analysis were compared with results obtained using the Cut Cell method. Casting flow simulations of actual products during various casting processes were also conducted, and these results were analyzed with and without applying the Cut Cell method.

• KSBB Journal
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• v.11 no.6
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• pp.663-668
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• 1996

In the production of recombinant protein using E. coli, phage lysogen system can be usefully applied for simultaneously achieving protein production at high cell concentration and recovery by cell disruption in the same bioreactor. A major drawback of this system is that the intracellular product and complex broth components are mixed together in culture broth and hence purification efficiency is reduced. With the E. coli double-lysogen system, the expanded bed adsorption is very useful because the pretreatment processes in a routine bioseparation process can be done in a single column operation, and therefore may contribute towards lowering the operating cost of overall recovery/purification process. In the operation of EBA, it has been observed that the change in broth feed volume does not influence much the protein recovery in a tested range. The amount of protein adsorption per mL of resin was increased from $3.44{\times}106unit to 5.28{\times}106unit$ by doubling the column length. By two-fold increase of the column diameter, the ratio of protein concentration in eluent to that in feed was increased from 0.8 to 2.1. It is concluded from the present investigation that the increase of column length and diameter is necessary to enhance the protein adsorption amount per volume of resin and protein concentration in the eluent. The development of resins with various physical properties will be necessary for more extensive application of EBA.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.169-177
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• 2012

In the development process of application systems, the most important works are analysis and design. Most of the application systems are implemented on database system. So, database design is important. Also, IT System are confronted with more and more attacks by an increase interconnections between IT systems. Therefore security-related processes belong to a very important process. Security is a complex non-functional requirement that can interaction of many parts in the system. But Security is considered in the final stages of development. Therefore, Their increases the potential for the final product to contain vulnerabilities. Accordingly, Early in development related to security analysis and design process is very important. J2EE gives a solution based on RBAC((Role Based Access Control) for security and object-relational database also has RBAC for security. But there is not a object-oriented analysis and design methodology using RBAC of J2EE and object-relational database for security. In this paper, the unified object-oriented analysis and design methodology is developed for security-critical web application systems based on J2EE and object-relational database. We used UMLsec and RBAC of object-relational database and J2EE for this methodology.

• Journal of Intelligence and Information Systems
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• v.23 no.4
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• pp.1-31
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• 2017

Modern businesses are adopting new technologies to serve their markets better as well as to improve efficiency and productivity. The advertising industry has continuously experienced disruptions from the traditional channels (radio, television and print media) to new complex ones including internet, social media and mobile-based advertising. This case study focuses on proposing intelligent advertising business model in Seoul's metro network. Seoul has one of the world's busiest metro network and transports a huge number of travelers on a daily basis. The high number of travelers coupled with a well-planned metro network creates a platform where marketers can initiate engagement and interact with both customers and potential customers. In the current advertising model, advertising is on illuminated and framed posters in the stations and in-car, non-illuminated posters, and digital screens that show scheduled arrivals and departures of metros. Some stations have digital screens that show adverts but they do not have location capability. Most of the current advertising media have one key limitation: space. For posters whether illuminated or not, one space can host only one advert at a time. Empirical literatures show that there is room for improving this advertising model and eliminate the space limitation by replacing the poster adverts with digital advertising platform. This new model will not only be digital, but will also provide intelligent advertising platform that is driven by data. The digital platform will incorporate location sensing, e-commerce, and mobile platform to create new value to all stakeholders. Travel cards used in the metro will be registered and the card scanners will have a capability to capture traveler's data when travelers tap their cards. This data once analyzed will make it possible to identify different customer groups. Advertisers and marketers will then be able to target specific customer groups, customize adverts based on the targeted consumer group, and offer a wide variety of advertising formats. Format includes video, cinemagraphs, moving pictures, and animation. Different advert formats create different emotions in the customer's mind and the goal should be to use format or combination of formats that arouse the expected emotion and lead to an engagement. Combination of different formats will be more effective and this can only work in a digital platform. Adverts will be location based, ensuring that adverts will show more frequently when the metro is near the premises of an advertiser. The advertising platform will automatically detect the next station and screens inside the metro will prioritize adverts in the station where the metro will be stopping. In the mobile platform, customers who opt to receive notifications will receive them when they approach the business premises of advertiser. The mobile platform will have indoor navigation for the underground shopping malls that will allow customers to search for facilities within the mall, products they may want to buy as well as deals going on in the underground mall. To create an end-to-end solution, the mobile solution will have a capability to allow customers purchase products through their phones, get coupons for deals, and review products and shops where they have bought a product. The indoor navigation will host intelligent mobile-based advertisement and a recommendation system. The indoor navigation will have adverts such that when a customer is searching for information, the recommendation system shows adverts that are near the place traveler is searching or in the direction that the traveler is moving. These adverts will be linked to the e-commerce platform such that if a customer clicks on an advert, it leads them to the product description page. The whole system will have multi-language as well as text-to-speech capability such that both locals and tourists have no language barrier. The implications of implementing this model are varied including support for small and medium businesses operating in the underground malls, improved customer experience, new job opportunities, additional revenue to business model operator, and flexibility in advertising. The new value created will benefit all the stakeholders.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1364-1373
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• 2016

Ultra High Definition Television (UHDTV) has attracted much attention as one of next generation broadcasting services. For the commercialization of UHD broadcasting service, standardization groups including the DVB (Digital Video Broadcasting) and the ATSC (Advanced Television Systems Committee) have decided to adopt the Orthogonal Frequency Division Multiplexing (OFDM) for signal transmission. However, when the carrier frequency is not properly synchronized at the receiver, inter-symbol interference (ISI) and inter-carrier interference (ICI) may occur. In order to avoid performance degradation resulting from ISI or ICI, receivers should synchronize the carrier frequency by using preambles and pilot symbols. However, there only few published literature dealing with the frequency offset estimation methods regarding the next generation terrestrial broadcasting. In this respect, this paper proposes a method to estimate timing and fractional frequency offset for the ATSC 3.0 system by using a preamble bootstrap symbol. The proposed detector can detect the fractional frequency offset by adding a complex conjugate product on the conventional estimator where only timing offset can be estimated.

• Proceedings of the Korean Society of Grassland Science Conference
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• 2002.09b
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• pp.131-156
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• 2002

Although economically viable, the livestock industry is currently facing a number of challenging environmental problems and highly complex social issues, many of which are related to its size and geographically concentrated nature. Increased emphasis on environmental quality has also placed new demands on livestock producers to ensure that their production practices are in harmony with natural environment. In terms of sustainable agricultural systems, ruminants have served and will continue to serve a valuable role. They are particularly useful in converting vast renewable resources from rangeland, pasture, and crop residues or other by-product into food edible for human. With ruminants, land that is too poor or too erodable to cultivate becomes productive. Also, nutrients in by-products are utilized and do not become a waste-disposal problem. In Korea, however, native and dairy cattle production is not consistent with the advantageous roles of ruminant livestock in sustainable agricultural system because imported feed grains become the main basis for cattle raising. At present the ruminant livestock producers are heavily concentrated in and around the urban areas. About 75% of all the nation's cattle herds are kept on the outskirts of urban areas. As a result, the amount of pasture and forage land available per head of cattle is generally small. Furthermore, animals are raised in a cattle shed with high density. This situation is rather unfavorable for the national economic and environmental points of view As nation income increased, the demand for livestock products grew at an unforeseeable pace. But the pasture area involving in current utilization is tended to decrease during recent years. Based on the above figures more than 250,000 ha of pasture ought to be available for the present herd of cattle. It is obvious that these needs can scarcely be met with arable lands. Lands area for the establishment of new grassland have to be found in the hills and mountains which have not yet been used for crop framing or livestock. The development of extensive grasslands in the hill and woodland areas is now a declared aim. The starting point of the present work is the lack of knowledge of forage production and utilization in hill pasture and woodland in spite of indispensable necessity for livestock production in Korea. The importance of pastoral system in hill region and woodland is particularly emphasized in a standpoint of sustainable livestock production. Main chapter comprises the principle and techniques applicable for improving the utilization of hill pasture and woodland. We finally discussed the problems to solve and future works for a successful livestock production in hill and mountainous area in Korea.

• Korean Journal of Social Welfare
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• v.59 no.3
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• pp.75-97
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• 2007

The purpose of this article is to explore French 'minima sociaux', focusing its scheme, benefit determination rule and its level appreciation. First, on the its structure domain, French 'minima sociaux' presents the plural system in which there is eight categorical benefits and one general benefit. Il is the representation of the intention to guarantee minimum income for the dead zone people out of the social insurance application and also a historical product in different period, by different logic of benefits implementation. Second, comparing nine benefits based on the benefit determination rule, level of benefits for the poor without work ability is higher than one for the poor with work ability. Il represents one polarized perception toward for the poor according to have or not its work ability. Third, comparing level of 'minima sociaux' with relative poverty line, the level of the most 'minima sociaux' is placed under the poverty line. Nevertheless, it must not forget that 'minima sociaux' plays its role as the fundamental alternative for poverty alleviation, but not the only alternative. Fourth and finally, comparing with minimum income guarantee(SMIC in french), level of RMI benefit is estimated merely on the 50% of SMIC. We can consider that it is the result of the interaction of the complex factors, as the limited role of the state toward the minimum income guarantee for the RMI beneficiary and the intervention the logic of status instead of the logic of need, etc..

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.230-234
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• 2007

Oxygen is required for many important aerobic cellular reactions, it may undergo electrontransfer reactions, which generate highly reactive membrane-toxic intermediates (reactive oxygen species, ROS), such as hydrogen peroxide, singlet oxygen, superoxide radical, hydroxyl radical, hydroperoxyl radical, hydroxy ion. Various mechanisms are available to protect cells against damage caused by oxidative free radicals, including scavenging enzyme systems such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). This antioxidant defense system is a very complex and finely tuned system consisting of enzymes capable of detoxifying oxygen radicals as well as low molecular weight antioxidants. In addition, repair and turnover processes help to minimize subcellular damage resulting from free radical attack. $H_2O_2$,one of the major ROS, is produced at a high rate as a product of normal aerobic metabolism. The primary cellular enzymatic defense systems against $H_2O_2$ are the glutathione redox cycle and catalase. From Northern blot analysis of total RNAs from cultured cell with $H_2O_2$ treatment, various results were obtained. Expression of Cu/Zn SOD decreased when cell passage increased, but the level of the Cu/Zn SOD was scarcely expressed in 35 passage.