• Journal of IKEEE
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• v.28 no.3
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• pp.458-464
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• 2024

This study proposes a fault-tolerant caching system to address the issue of caching content imbalance caused by the dynamic departure and participation of cache servers in a heterogeneous cache server network, and validates it in both real and virtual environments. With the increase of large-scale media content requiring various types and resolutions, the necessity of cache servers as key components to reduce response time to user requests and alleviate network load has been growing. In particular, research on heterogeneous cache server networks utilizing edge computing and low-power devices has been actively conducted recently. However, in such environments, the irregular departure and participation of cache servers can occur frequently, leading to content imbalance among the cache servers deployed in the network, which can degrade the performance of the cache server network. The fault-tolerant caching algorithm proposed in this study ensures stable service quality by maintaining balance among media contents even when cache servers depart. Experimental results confirmed that the proposed algorithm effectively maintains content distribution despite the departure of cache servers. Additionally, we built a network composed of seven heterogeneous cache servers to verify the practicality of the proposed caching system and demonstrated its performance and scalability through a large-scale cache server network in a virtual environment.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.344-350
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• 2003

In this paper, we propose a novel sharing method ordering the events occurring between users collaborated with the common telecomputing environment. We realize the sharing method with multimedia data to improve the coworking effect using teleprocessing network. This sharing method advances the efficiency of communicating projects such as remote education, tele-conference, and co-authoring of multimedia contents by offering conveniences of presentation, group authoring, common management, and transient event productions of the users. As for the conventional sharing white board system, all the multimedia contents segments should be authored by the exclusive program, and we cannot use any existing contents or program. Moreover we suffer from the problem that ordering error occurs in the teleprocessing operation because we do not have any line-up technology for the input ordering of commands. Therefore we develop a method of retrieving input and output events from the windows system and the message hooking technology which transmits between programs in the operating system In addition, we realize the allocation technology of the processing results for all sharing users of the distributed computing environment without any error. Our sharing technology should contribute to improve the face-to-face coworking efficiency for multimedia contents authoring, common blackboard system in the area of remote educations, and presentation display in visual conference.

• Journal of Internet Computing and Services
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• v.14 no.5
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• pp.101-117
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• 2013

As the number of online game user has been rapidly increased thanks to the recent vitalization of online contents market, not only new business opportunity but also the opportunity to create high profits have been provided as well. However, the increase of the number of online game user and the rapid expansion of the market evoke a cutthroat completion among online game service providers, and also high barriers to entry to online game market have been erected. Thus, what kinds of efforts need for the business success and sales increase in online game market? In lots of researches regarding online contents business, the deepening of loyalty was considered as a critical factor for the business success. According to the study on user's behavior in online environment, users would experience the Flow while using online service, and then, if they were in state of the Flow, they would use the service constantly. High customer loyalty to online game means high will to use the online game too. The purpose of this research was i) to examine what factors enable users to be naturally immersed in online game while playing it, ii) to examine what properties of online game can make game more interesting and exciting, iii) to verify that such factors are critical in deepening customer loyalty, and iv) to suggest some essential factors to be fun and exciting games, on where the focus should be put, and the directionality for the development for sales expansion of online game developer or online game service provider. The research results are as below: First, the involvement and the perceived quality which were characteristics of brand appeared to be factors most affecting Flow. This shows that once game user get interested in online game that user has played frequently, even though new games are released, user will continuously flow the game not moving to new games, and also shows that users not only get more interested but also put more trust in games in the site to where users are frequently going than games in other sites, and consequently user can increasingly flow the game. Second, the compensation and graphics which are the characteristics of contents appeared to be factors affecting Flow. Proper compensation which is given to game users triggers fun and interests in game and makes them flow more and more. And graphics make users to feel game space as if real space and let them flow in game with more reality. Third, challenges, support, and the stability which are technical characteristics appeared to be factors affecting Flow. Challenges enable users to not only experience new virtual world but also solve various difficulties and obstacles. Once users feel fun and interests through this challenge, they can naturally flow games. In addition, the stability of network provides reliability in security and hacking. By doing so, it can induce users to flow more and more. Lastly, when aforementioned characteristics including contents characteristics, technical characteristics, and brand characteristics are organically combined each other, game users feel fun and total minutes are naturally increased, so that game users experience Flow, and consequently the customer loyalty will be deepened as well.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.476-487
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• 2007

Flash memory offers attractive features, such as non-volatile, shock resistance, fast access, and low power consumption for data storage. However, it has one main drawback of requiring an erase before updating the contents. Furthermore, flash memory can only be erased limited number of times. To overcome limitations, flash memory needs a software layer called flash translation layer (FTL). The basic function of FTL is to translate the logical address from the file system like file allocation table (FAT) to the physical address in flash memory. In this paper, a new FTL algorithm called an efficient and advanced space-management technique (EAST) is proposed. EAST improves the performance by optimizing the number of log blocks, by applying the state transition, and by using reallocation blocks. The results of experiments show that EAST outperforms FAST, which is an enhanced log block scheme, particularly when the usage of flash memory is not full.

• Computers and Concrete
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• v.26 no.4
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• pp.327-342
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• 2020

The objective of this study is to manufacture environmentally-friendly synthetic lightweight aggregates that may be used in the structural lightweight concrete production. The cold-bonding pelletization process has been used in the agglomeration of the pozzolanic materials to achieve these synthetic lightweight aggregates. In this context, it was aimed to recycle the waste fly ash by employing it in the manufacturing process as the major cementitious component. According to the well-known facts reported in the literature, it is stated that the main disadvantage of the synthetic lightweight aggregate produced by applying the cold-bonding pelletization technique to the pozzolanic materials is that it has a lower strength in comparison with the natural aggregate. Therefore, in this study, the metakaolin made of high purity kaolin and calcined kaolin obtained from impure kaolin have been employed at particular contents in the synthetic lightweight aggregate manufacturing as a cementitious material to enhance the particle crushing strength. Additionally, to propose a curing condition for practical attempts, different curing conditions were designated and their influences on the characteristics of the synthetic lightweight aggregates were investigated. Three substantial features of the aggregates, specific gravity, water absorption capacity, and particle crushing strength, were measured at the end of 28-day adopted curing conditions. Observed that the incorporation of thermally treated kaolin significantly influenced the crushing strength and water absorption of the aggregates. The statistical evaluation indicated that the investigated properties of the synthetic lightweight aggregate were affected by the thermally treated kaolin content more than the kaoline type and curing regime. Utilizing the thermally treated kaolin in the synthetic aggregate manufacturing lead to a more than 40% increase in the crushing strength of the pellets in all curing regimes. Moreover, two numerical formulations having high estimation capacity have been developed to predict the crushing strength of such types of aggregates by using soft-computing techniques: gene expression programming and artificial neural networks. The R-squared values, indicating the estimation performance of the models, of approximately 0.97 and 0.98 were achieved for the numerical formulations generated by using gene expression programming and artificial neural networks techniques, respectively.

• Journal of the Korean Dietetic Association
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• v.8 no.1
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• pp.9-18
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• 2002

This study was reviewed databases and outcomes of national/international off-line and on-line(Internet) nutrition softwares to identify the present conditions of nutrition softwares, and investigated user's needs and determine which component should be included in nutrition software. The most frequently used databases for the national programs were the food composition table provided from the National Rural Living Science Institution in Rural Development Administration and the food composition table and the nutrient contents of foods provided from the Korean Nutrition Society. For international programs, the food composition table from the USDA was commonly used. The analysed outcomes included the degree of obesity, nutrient analysis and nutrient intake compared with RDA, food intake from each by food group, food habits and the frequency of food consumption. As to the result of needs assessment for the Internet nutrition softwares, it was suggested that the needs of the Internet nutrition softwares were high because most of the respondents replied that 3-point('it is needed') or 4-point('it is necessary') on 4-points likert scale. As to the databases, the needs of 'food composition analysis' and 'the suggestion of the Korean RDA' were high. For the basic information for foods, the respondents replied that 'the classification of foods', 'foods codes', 'the amount of ingredients' and 'nutrient analysis' should be included. The needs of 'nutrient analysis of meal', 'diet therapy' and 'meal plan by caloric requirements' were high. As for utilizing the Internet meal planning programs, the respondents replied that 'it should be easy to use' most and demand for 'data saving and the saved data should be usable later' and 'meal planning education tools' were high. In conclusion, the Internet nutrition software that satisfies various needs of users should be developed for policy making that promote public health, nutritional care and self-supporting of foods.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.57-64
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• 2020

Today, with the development of information technology, hospitals are actively researching hospital information systems that are not limited by time and space to integrate mobile computing technology into the medical field to manage the bulk data of medical information. Nevertheless, most hospitals still spend a lot of time and effort creating manual schedules. In this paper, we studied an optimization model for organizing nurses' shift work and constructed an automated nurse-type job organization system. For nurses working in S hospital, information data, requirements and constraints of nurses were constructed. By applying this, we proposed an optimized scheduling method and built a web-based platform used by head nurses and a mobile app platform used by general nurses to enable real-time interchange and sharing around web servers. Therefore, through the developed nurse needs type automated system, the head nurses will increase the convenience of the nurses to organize the work every month, and general nurses will help them to work more accurately through personal schedule management. It is also expected to increase work efficiency by sharing work schedules among nurses.

• Journal of Digital Convergence
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• v.10 no.1
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• pp.277-291
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• 2012

Smartphone (smartpad) and cloud computing has grown rapidly. So, the users started getting interested in multi-screen services. However, various OS / platforms due to the increased content development time and cost. Increase the cost of content development for a multi-screen service, it has been an obstacle. To solve this problem in this study, HTML5-based multi-screen service platform standards specification was established. HTML5 is a specification of the next generation of Web standards. Standards specification established by this study were research in terms of the service provider. And, this standards specification can be used independently of the service infrastructure and device. In addition, this standards specification in order to develop a multi-screen services are efficient and easy to use. For verification adequacy of standards specification established in this study, Scenarios technical entries were mapped by standard specification entries.

• Journal of Internet Computing and Services
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• v.3 no.5
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• pp.51-62
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• 2002

The development of computer technology and the advancement of the technology of information and communications spread the technology of multimedia and increased the use of multimedia data with large capacity, Users can grasp the overall video data and they are able to play wanted video back. To grasp the overall video data it is necessary to offer the list of summarized video data information, In order to search video efficiently on index process of video data is essential and it is also indispensable skill, Therefore, this thesis suggested the effective method about the cut detection of frames which will become a basis of an index based on contents of video image data. This suggested method was detected as the unchanging pixel color intelligence value, classified into diagonal direction. Pixel value of color detected in each frame of video data is stored as A(i, j) matrix-i is the number of frames. j is an image height of frame. By using the stored pixel value as the method of sum of squared difference of color two frames I calculated a specified value difference between frames and detected cut quickly and exactly in case it is bigger than threshold value set in advance, To carry out on experiment on the cut detection of frames comprehensively, I experimented on many kinds of video. analyzing and comparing efficiency of the cut detection system.

• Journal of Internet Computing and Services
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• v.17 no.4
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• pp.27-34
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• 2016

The referents of internet addresses are no longer limited to web sites. A new address service by the international organization for the internet address (ICANN) introduces an open space for the TLD (Top Level Domain) strings so that each service, content, product, and other linguistic expressions may be allowed. The open TLD addresses are more suitable for representing the address of service units, contents, or products. In this paper, as an alternative to static Internet address service to return a consistent mapping result regardless of a user-specific different requirements, we design a dynamic internet address mapping model that returns mapping result to suit user particular requirements. In addition, we propose a method for implementing a internet address service without any changes in the existing domain protocols. It may implement a dynamic internet address by attaching to a encoded user's metadata and environment data within a internet address representation, and adding the module for dynamic mapping to the name servers. Through this proposal, trying to expand the functions of internet address, it is expected to be able to provide customized informaiton retrieval services for each user by using just internet address.