• Journal of National Security and Military Science
• /
• s.2
• /
• pp.237-260
• /
• 2004

As the research work about XML based on the development of Internet and according to the information exchange standard is being carried out, the need of discovering new methods to store XML documents and manage them efficiently according to the frequency of large-capacity XML documents increases. Consequently, as a kind of back-end database system, XML storage systems such as RDBMS, OODBMS and Native XML DBMS etc. are coming forth in order to save XML documents. It is an urgent task to make comparisons among usage expense, function comparison storage, inquiry, and manage dimension for each DBMS. This paper makes an analysis and comparison of DTD-independent XML document access methods in RDBMS, OODBMS and Native XML DBMS for XML storage and management. After analyzing the advantages and disadvantages of each access method and comparing the function of typical commerce DBMS such as Oracle 8i, eXcelon and Tamino for finding the possibility of military applications, an another appropriate method to save XML documents is proposed as to find an implementation approach to save structural XML documents.

• Fire Science and Engineering
• /
• v.33 no.6
• /
• pp.173-180
• /
• 2019

Oil tank fires need to be suppressed differently from other oil-related fires, due to the high-temperature flames and hot updraft above the tank, in the former case, that cause the destruction of large amounts of foam. We studied high-capacity foam discharge systems based on the standards of the American Petroleum Institute (API), National Fire Protection Association (NFPA), British Standard European Norm (BS EN), and the laws of Japan. The performance of a high-capacity foam discharge system was measured by conducting real fire experiments with model oil tanks. We concluded that lightweight and easily movable high-capacity foam discharge systems should be urgently introduced in domestic operations. Additionally, the obstacles faced by major tanks, such as long-distance installation of large-diameter fire hoses and narrowing of firefighting spaces, should be resolved depending on the conditions of the site.

• Korean Institute of Interior Design Journal
• /
• v.22 no.5
• /
• pp.328-335
• /
• 2013

This study investigated the ratios of area, according to the domains and functions, of a public library. To this end, 20 public libraries were selected as samples from the 2012 Public Library Construction Casebook and from cases of consulting on the construction and operation of public libraries. The domains of a public library were categorized into data reading, cultural education, operation, common use, and others. There was a large difference in the area ratios between public libraries that were built with the aid of consulting (Group B) and those without consulting (Group A). In functional terms, the data(bookshelf) space and reading space had similar ratios within a data reading room, while the ratio of the library information space was smaller. Within a general data reading room, the ratio of the library information space was 12%, while the ratios of the data space and seating space were 44%, respectively. Moreover, within a data reading room for children, the ratios of the library information space and children's space were adjusted to 14%, respectively, while the data space and seating space each accounted for 36%, with either 3- or 5-decker bookshelves installed. This study has identified how to calculate the area for each domain, capacity of books, and seating capacity by applying area ratios through functions in the data storage domain, along with numbers of books and seats per unit space. This study has also succeeded in calculating the required area and seats for each type of data storage room by applying the number of books that exist. However, this study has its limitation in that the regional characteristics(Metropolis, Small & medium size cities, Rural areas) were not considered because the number of samples was only 20 libraries.

• Applied Chemistry for Engineering
• /
• v.20 no.5
• /
• pp.465-472
• /
• 2009

The technologies for improving the capacity of hydrogen storage were investigated and the recent data of hydrogen storage by using various porous carbon materials were summarized. As the media of hydrogen storage, activated carbon, carbon nanotube, expanded graphite and activated carbon fiber were mainly investigated. The hydrogen storage in the carbon materials increased with controlled pore size about 0.6~0.7 nm. In case of catalyst, transition metal and their metal oxide were mainly applied on the surface of carbon materials by doping. Activated carbon is relatively cheap because of its production on a large scale. Carbon nanotube has a space inside and outside of tube for hydrogen storage. In case of graphite, the distance between layers can be extended by intercalation of alkali metals providing the space for hydrogen adsorption. Activated carbon fiber has the high specific surface area and micro pore volume which are useful for hydrogen storage. Above consideration of research, porous carbon materials still can be one of the promising materials for reaching the DOE target of hydrogen storage.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.3
• /
• pp.7-12
• /
• 2016

DRAM is commonly used as a smartphone memory medium, but extending its capacity is challenging due to DRAM's large battery consumption and density limit. Meanwhile, smartphone applications such as social network services need increasingly large memory, resulting in long latency due to additional storage accesses. To alleviate this situation, we adopt emerging nonvolatile memory (NVRAM) as smartphone's buffer cache and propose an efficient management scheme. The proposed scheme stores all dirty data in NVRAM, thereby reducing the number of storage accesses. Moreover, it separately exploits read and write histories of data accesses, leading to more efficient management of volatile and nonvolatile buffer caches, respectively. Trace-driven simulations show that the proposed scheme improves I/O performances significantly.

• Steel and Composite Structures
• /
• v.23 no.2
• /
• pp.143-152
• /
• 2017

This paper focuses on the seismic performance of pallet-type steel storage rack structures in their down aisle direction. As evidenced by experimental research, the seismic response of storage racks in the down-aisle direction is strongly affected by the nonlinear moment-rotation response of the beam-to-column connections. In their down-aisle direction, rack structures are designed to resist lateral seismic loads with typical moment frames utilizing proprietary beam-to-column moment-resisting connections. These connections are mostly boltless hooked type connections and they exhibit significantly large rotations resulting in large lateral frame displacements when subjected to strong ground motions. In this paper, typical hooked boltless beam-to-column connections are studied experimentally to obtain their non-linear reversed cyclic moment-rotation response. Additionally, a compound type connection involving the standard hooks and additional bolts were also tested under similar conditions. The simple introduction of the additional bolts within the hooked connection is considered to be a practical way of structural upgrade in the connection. The experimentally evaluated characteristics of the connections are compared in terms of some important performance indicators such as maximum moment and rotation capacity, change in stiffness and accumulated energy levels within the cyclic loading protocol. Finally, the obtained characteristics were used to carry out seismic performance assessment of rack frames incorporating the tested beam-to-column connections. The assessment involves a displacement based approach that utilizes a simple analytical model that captures the seismic behavior of racks in their down-aisle direction. The results of the study indicate that the proposed method of upgrading appears to be a very practical and effective way of increasing the seismic performance of hooked connections and hence the rack frames in their down-aisle direction.

• Journal of Digital Contents Society
• /
• v.8 no.3
• /
• pp.393-401
• /
• 2007

P2P systems have gained a lot of research interests and popularity over the years and have the capability to unleash and distribute awesome amounts of computing power, storage and bandwidths currently languishing - often underutilized - within corporate enterprises and every Internet connected home in the world. Since there is no central control over resources or devices and no before hand information about the resources or devices, device discovery remains a substantial problem in P2P environment. In this paper, we cover some of the current solutions to this problem and then propose our feed forward neural network (FFNN) based solution for device discovery in mobile P2P environment. We implements feed forward neural network (FFNN) trained with back propagation (BP) algorithm for device discovery and show, how large computation task can be distributed among such devices using agent technology. It also shows the possibility to use our architecture in home networking where devices have less storage capacity.

• Journal of the Korea Society for Simulation
• /
• v.8 no.2
• /
• pp.29-43
• /
• 1999

As real-time processing of data with large storage space is required in the era of multimedia, disk arrays are generally used as storage subsystems which be able to provide improved I/O performance. To design the cost-effective disk array, it is important to develop performance models which evaluate the disk array performance. Both queueing theory and simulation are applicable as the method of performance evaluation through queueing modeling. But there is a limit to the analytical method using queueing theory due to the characteristics of disk array requests being serviced in the parallel and concurrent manner. So in this paper we evaluate the disk array performance using simulation method which abstract disk array systems in the low level. Performance results were evaluated through simulation, so that mean response time, mean queueing delay, mean service time, mean queue length for disk array requests and utilization, throughput for disk array systems, can be utilized for capacity planning in the phase of disk array design.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.2
• /
• pp.47-53
• /
• 2015

The study concerning about the grid connection of the large-capacity energy storage system(ESS) is increasing. However, the transient study such as lightning or switching surge necessarily occurred at power system with ESS has been hardly performed. Therefore, this paper performs the analysis of lightning surge in distribution system with ESS using electromagnetic transient program(EMTP). The battery model in Matlab/Simulink is modeled by EMTP, which is the specialized software for power system transient study. Also, the bi-directional power electronics for interconnection of the battery and distribution system are modeled by EMTP. When the lightning is occurred at interconnection point of ESS, this paper simulates the existence of ESS and operation conditions of ESS and analyzes the surge in distribution system and ESS according to the various conditions.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.4
• /
• pp.378-383
• /
• 2010

Due to the large capacity and low cost, DC link electrolytic capacitors with of energy storage and voltage regulation are used for almost all types of power converter as the DC/AC inverter or DC/DC converter. Electrolytic capacitor, which is the most of the time affected by the aging effect, plays very important role for the power converter system quality and reliability. Therefore, this paper proposes a simple method to estimate the capacitance variation of an electrolytic capacitor in order to analyze the internal characteristic decrease and worn-out state of an electrolytic capacitor. Simulation results by using capacitor storage energy computation show the validity of the proposed capacitance estimation method.