• Journal of the Korean Magnetics Society
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• v.21 no.4
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• pp.136-140
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• 2011

Mechanical properties of degraded materials must be measured for evaluating the integrity of the facilities operating at high temperature. In fact it is complicated to obtain the different degraded specimens from an operating facility. Specimens of 1Cr-0.5Mo steel prepared by the isothermal heat treatment at $700^{\circ}C$ were tested, which has been widely used as tubes for heat exchangers and as plates for pressure vessels. The magnetic properties and Rockwell hardness (HRB) were measured at room temperature. The peak interval of Barkhausen noise envelope (PIBNE), coercivity, and hardness decreased with the increase of degradation. The magnetic and mechanical softening of matrix is likely to govern the properties of the specimen more than the hardening of grain boundary by carbide precipitations. The degradation of test material may be determined by the linear correlation of PIBNE and HRB. Degradation of 1Cr-0.5Mo steel could well be nondestructively evaluated by PIBNE measured with surface type probe.

• Trans-
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• v.4
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• pp.37-63
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• 2018

Dance films, which started together as a combination of dance and video technology, have evolved into a new genre. Overseas, from early 1950s, experimental dance films have been produced and the dance film association is organized along with many dance film festivals are being held. However, it has not been long since the perception and creativity of the genre of dance films in Korea. Under these circumstances, holding of the 'Seoul Dance Film Festival' and experimental approaches by 'Dance Film Project' are important for the development of domestic dance films. Therefore, this paper explores the concept and development of dance films, the status and features of various overseas dance film festivals and the 'Seoul Dance Film Festival'. This paper also explores the roll and function of 'Seoul Dance Film Festival' and 'Dance Film Project', and their expected benefit along with possibilities of prosperity of domestic dance film. 'Dance Film Project' is the educational and experimental venue for producing of dance films, and the 'Seoul Dance Film Festival' is a platform for producing dance film makers, show of works, dialogue with audiences, international exchanges, and distributions. The dance film festival embodies the value of the past and current flow of the dance film and is intrinsic to the existence of a live content that can be predicted the future aspect of its roll. The two groups mutual growth and development are expected to play a positive role in the development of domestic dance films.

• Journal of Life Science
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• v.20 no.7
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• pp.1143-1150
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• 2010

The antibacterial activity of methanol extracts from 70 kinds of oriental medicinal herbs on four strains of Staphylococcus aureus and S. epidermidis was investigated. The results showed that C. japonica, C. sappan, R. javanica, R. tanguticum, and S. miltiorrhiza had an antibacterial activity on all the strains used. Among these, C. japonica and R. javanica, which showed excellent antibacterial activity, were extracted with water, ethanol, methanol, and ethyl acetate for further study of antibacterial activities. The results showed that the boiled water extract of C. japonica had the best antibacterial activity. Assuming that the antibacterial activity of C. japonica originated from berberine, which has been reported many times, the berberine content of the boiled water extract of C. japonica was analyzed and the result was 13.88%. To compare the antibacterial activity of berberine with that of other antibiotics, berberine chloride and three other kinds of antibiotics were investigated, which showed that berberine chloride had an antibacterial activity on KCCM 35494 S. epidermidis only when the concentration was higher than 600 mg/l, and it did not show antibacterial activity in the other strains. Based on these results, it was concluded that the antibacterial activity of the boiled water extract of C. japonica on the strains used in this study originated from high concentration of berberine or substances other than berberine. Therefore, identification of the substance will be necessary.

• Korean Journal of Materials Research
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• v.8 no.10
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• pp.961-968
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• 1998

In order to investigate the effects of substrate bias voltage on the formation of$ZnS-SiO_2$ protective film in phase change optical disk by R.F. magnetron sputtering method, thin dielectric film was formed on Si wafer and Corning glass by using ZnS(80mol%)-$SiO_2$(20mol%)t arget under argon gas. In this study, the Taguchi experimental method was applied in order to obtain optimum conditions with reduced number of experiments and to control numerous variables effectively. At the same time this method can assure the reproducibility of experiments. Optimum conditions for film formation obtained by above method were target RF power of 200 W. substrate RF power of 20 W, Ar pressure of 5 mTorr. sputtering time of 20 min.. respectively. The phase of specimen was determined by using XRD and TEM. The compositional analysis of specimen was performed by XPS test. In order to measure the thermal resistivity of deposited specimen, annealing test was carried out at $300^{\circ}C$ and $600^{\circ}C$. For the account of void fraction in thin film, the Bruggeman EMA(Effective Medium Approximation) method was applied using the optical data obtained by Spectroscopic Ellipsometry. According to the results of this work, the existence of strong interaction between bias voltage and sputtering time was confirmed for refractive index value. According to XRD and TEM analysis of specimen, the film structure formed in bias voltage resulted in more refined structures than that formed without bias voltage. But excess bias voltage resulted in grain growth in thin film. It was confirmed that the application of optimum bias voltage increased film density by reduction of void fraction of about 3.7%.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.2
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• pp.223-266
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• 2020

Massively Multiplayer Online Role-Playing Games (MMORPGs) are played by millions of people around the world. Within MMORPGs, players explore, solve mysteries, craft items, battle against dungeon or raid bosses, or compete against other players, all while using a variety of information and information behaviors. Role-players in MMORPGs develop identities and engage in interactive storytelling with other role-players as their characters. An ethnographic approach combining overt participant observation and engagement, semi-structured interviews, and artifact collection was used to explore and describe the social information behaviors of role-players through the lens of the theory of information worlds. The social types evident in the role-playing community in WildStar, a science fantasy-themed MMORPG, are closely interrelated to and differentiated by social norms and information values that dictate acceptable characters, stories, character actions, and appropriate lore sources as well as how to role-play without violating the boundary between in- and out-of-character information worlds. Role-players maintained the in-character and out-of-character boundary using a set of specific information behaviors to enable engaging and immersive role-playing experiences. Implications of the findings for the theory of information worlds as well as potential applications of role-playing and MMORPGs are also discussed.

• Journal of the Korea Computer Graphics Society
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• v.17 no.3
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• pp.1-7
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• 2011

Recently, various researches have been proposed to accelerate GPU-based volume ray-casting. However, those researches may cause several problems such as bottleneck of data transmission between CPU and GPU, requirement of additional video memory for hierarchical structure and increase of processing time whenever opacity transfer function changes. In this paper, we propose an efficient GPU-based empty space skipping technique to solve these problems. We store maximum density in a brick of volume dataset on a vertex element. Then we delete vertices regarded as transparent one by opacity transfer function in geometry shader. Remaining vertices are used to generate bounding boxes of non-transparent area that helps the ray to traverse efficiently. Although these vertices are independent on viewing condition they need to be reproduced when opacity transfer function changes. Our technique provides fast generation of opaque vertices for interactive processing since the generation stage of the opaque vertices is running in GPU pipeline. The rendering results of our algorithm are identical to the that of general GPU ray-casting, but the performance can be up to more than 10 times faster.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1257-1269
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• 2010

The internet which is fast spread over all areas of our lives provides us with benefits of efficiency, productivity, and amusement; however, its features as an anonymous and non-face-to-face medium have raised a serious social issue of the collapse of internet ethics due to the abuse of it. Thereupon, the importance of internet ethics education has been highlighted to prevent side effects resulted from the internet and cultivate human-centered internet culture. In this paper, we suggests desirable methods for internet ethics education based on the investigation and analysis of the status of university freshmen's internet ethics. This research conducted a survey and analyzed its result after categorizing the status of internet ethics into the invasion of private information, invasion of intellectual property rights, harmful information, internet communication culture, cyber violence, internet addiction, and internet fraud. And based on the result of analyzing their internet ethics, this paper suggests desirable methods for internet ethics education. Next, internet ethics education was conducted by applying the proposed methods for internet ethics education, and its educational effect was evaluated. According to the result of verifying the educational effect measured statistically, it has proved that the suggested internet ethics education is effective to improve undergraduates' internet ethics.

• Journal of KIISE:Databases
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• v.28 no.3
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• pp.512-527
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• 2001

In a client-server spatial database, it is desirable to maintain the cached data in a client side to minimize the communication overhead across a network. This paper deals with the issues of concurrency and consistency of map updates in this environment. A client transaction to update map data is an interactive work and takes a long time to complete it. The map update in a client site may affect the other sites'updates because of dependencies between spatial data stored at different sites. The concurrent updates should be propagated to the other clients as well as the server to keep the consistency of map replicated in a client cache, and also the communication overhead of the update propagation should be minimized not to lose the benefit of caching. The newly proposed cache region locking with CR lock and CX lock controls the update dependency due to spatial relationships. CS lock and COD lock are suggested to use optimistic detection-based approaches for guaranteeing the consistency of cached client data. The cooperative update protocol uses these extended locking primitives and Spatial Relationship-based 2PC (SR-based 2PC). This paper argues that the concurrent updates of cached client spatial data can be achieved by deciding on collaborative updates or independent updates based on spatial relationships.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2852-2859
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• 1997

Video-On-Demand system provides electronic video rental services from remote video servers on a broadband communication networks. Most of proposed VOD systems are typically designed for one-to-one conncetion between a user and video server. Therefore, video server stream services to customers individually by allocating a dedicated transmission channel and a set of video server resources for each customer. However, it is inefficiency and wxpensive way when server support multiple users who access the same video stream with a dedicated video channel. Therefore, to achieve cost-effectiveness, batching have studied method that uses multicast communication to simultaneously service all users requesting the same video with a single video with a single video stream. However, the application of the multicast communication by batching detract from the VCR-like function and on-demand nature of the system. In this paepr, we propose a scheme that can support an interactive VCR for all user requesting the same video stream with batching. To reduce a server I/O and network bandwidth requirement, dynamic buffer is allocated to access node which has variable playout poit. Consequently, it makes possible interactive VCR operation as if customer uses true VOD system. Also, this scheme can just deliver a multicast stream without delay after an initial request or VCR action occurred. The policy can guarantee acceptable services to number of users at minimum cost.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.107-114
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• 2002

In these days, rapid advances of the computer system and the high speed network have made the multimedia services popularized among various applications and services in the internet. Internet live broadcasting, a part of multimedia services, makes it possible to provide not only existing broadcasting services including audio and video but also interactive communications which also expand application scopes by freeing from both temporal and spatial limitation. In the Paper, an interned Personal-live broadcasting server system is developed by allowing individual users to actively create or join live-broadcasting services with such basic multimedia devices as a PC camera and a sound card. As the number of broadcasters and participants increases, concurrent multiple channels are established and groups are to be expanded. The system should also guarantee High Availability (HA) for continuous services even in the presence of partial failure of the cluster. Furthermore, a transmission mode switching is supported to consider network environments in the user system.