• Journal of the Korea Society of Computer and Information
• /
• v.14 no.3
• /
• pp.57-64
• /
• 2009

XML has become a do facto standard for structured document and data on the Web. An XML data deluge over the network will be more, since XML based standards such as Web Service and Semantic Web gets popular. There are efforts to store and query XML documents in a relational database system and recent efforts focus on how to provide such operations using XPath and XQuery. In this paper, we present study about those research efforts and we propose a new scheme to stoγe and query XML documents in a relational database using XPath query. The scheme uses a 'shred' method to store and translates XPath queries to SQL. We also present our empirical experiments using a RDBMS.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.12
• /
• pp.109-117
• /
• 2009

In this paper, we propose an efficient service discovery scheme that combines peer-to-peer caching advertisement and node ID-based selective forwarding service requests. P2P caching advertisement quickly spreads available service information and reduces average response hop count since service information store in neighbor node cache. In addition, node ID-based service requests can minimize network transmission delay and can reduce network load since do not broadcast to all neighbor node. Proposed scheme does not require a central lookup server or registry and not rely on flooding that create a number of transmission messages. Simulation results show that proposed scheme improved network loads and response times since reduce a lot of messages and reduce average response hop counts using adaptive selective nodes among neighbor nodes compared to traditional flooding-based protocol.

• The Journal of the Acoustical Society of Korea
• /
• v.41 no.2
• /
• pp.143-149
• /
• 2022

In this paper, we evaluate the underwater frequency diversity communication performance of Selective Combination (SC) using Maximum Likelihood Estimation (MLE). In an underwater multipath frequency selective channel, destructive interference fading due to delay spread of a received signal affects the increase in error and Signal to Noise Ratio (SNR) variability of an underwater acoustic communication. Selective Combination frequency diversity using a single sensor is applied as a transmission performance improvement technique according to the frequency selectivity of a channel. In the sea experiment applying MLE for SC decision value extraction, we evaluate the performance of SC frequency diversity and MLE-SC frequency diversity. In experiment result, we confirm through experiment that the Bit Error Rate (BER) is relatively lower when the decision value extracted through MLE-SC is applied than when the SC decision value is fixed.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.7 no.6
• /
• pp.839-849
• /
• 2017

Recently, the role of the kitchen has evolved from the space for previous survival to the space that shows the present life and culture. Along with these changes, the use of IoT technology is spreading. As a result, the development and diffusion of new smart devices in the kitchen is being achieved. The user experience for using these smart devices is also becoming important. For a natural interaction between a user and a computer, better interactions can be expected based on context awareness. This paper examines the Natural User Interface (NUI) that does not touch the device based on the user interface (UI) of the smart device used in the kitchen. In this method, we use the image processing technology to recognize the user's hand gesture using the camera attached to the device and apply the recognized hand shape to the interface. The gestures used in this study are proposed to gesture according to the user's context and situation, and 5 kinds of gestures are classified and used in the interface.

• Convergence Security Journal
• /
• v.22 no.5
• /
• pp.145-154
• /
• 2022

Recently, the widespread proliferation and high sophistication of botnets are having serious consequences not only for enterprises and users, but also for cyber warfare between countries. Therefore, research to detect botnets is steadily progressing. However, the DGA-based botnet has a high detection rate with the existing signature and statistics-based technology, but also has a high limit in the false positive rate. Therefore, in this paper, we propose a detection model using text-based n-gram to detect DGA-based botnets. Through the proposed model, the detection rate, which is the limit of the existing detection technology, can be increased and the false positive rate can also be minimized. Through experiments on large-scale domain datasets and normal domains used in various DGA botnets, it was confirmed that the performance was superior to that of the existing model. It was confirmed that the false positive rate of the proposed model is less than 2 to 4%, and the overall detection accuracy and F1 score are both 97.5%. As such, it is expected that the detection and response capabilities of DGA-based botnets will be improved through the model proposed in this paper.

• Convergence Security Journal
• /
• v.22 no.1
• /
• pp.29-38
• /
• 2022

The importance of prevention of epidemics is increasing due to the serious spread of infectious diseases. For prevention of epidemics, we need to focus on the non-contact industry. Therefore, in this paper, a face recognition door lock that controls access through non-contact is designed and developed. First very simple features are combined to find objects and face recognition is performed using Haar-based cascade algorithm. Then the texture of the image is binarized to find features using LBPH. An non-contact door lock system which composed of Raspberry PI 3B+ board, an ultrasonic sensor, a camera module, a motor, etc. are suggested. To verify actual performance and ascertain the impact of light sources, various experiment were conducted. As experimental results, the maximum value of the recognition rate was about 85.7%.

• Analytical Science and Technology
• /
• v.21 no.1
• /
• pp.48-52
• /
• 2008

A new forensic saliva test method using $SALIgAE^{(R)}$ was evaluated in this study. The sensitivity and specificity of $SALIgAE^{(R)}$ were examined and compared to those of other saliva test methods such as agarose gel diffusion method and $Phadebas^{(R)}$ test sheet method. $SALIgAE^{(R)}$ showed high sensitivity and specificity to human saliva in addition to quickness. Moreover modified $SALIgAE^{(R)}$ method was cheap and easy to use in crime scene and DNA laboratory. $SALIgAE^{(R)}$ was very stable at room temperature and had no effect on STR typing.

• Journal of the Korean Society of Safety
• /
• v.10 no.3
• /
• pp.120-129
• /
• 1995

Since the rate and completeness of combustion in direct injection engines were controlled by the characteristics of gas flow fields and sprays, an understanding of those was essential to the design of the direct injection engines. In this study the numerical simulations of swirl effects on the characteristics of gas flow fields and sprays were performed using the spray model that could predict the interactions between gas fields and spray droplets. The governing equations were discretized by the finite volume method and the modified k- e model which included the compressibility effects due to the compression/expansion of piston was used. The results of numerical calculation of the spray characteristics in the quiescent environment were compared with the experimental data. There were good agreements between the results of calculation and the experimental data, except in the early stages of spray. In the motoring condition, the results showed that a substantial air entrainment into the spray volume was emerged and hence the squish motion was relatively unimportant during fuel injection periods. As the swirl ratio increased, the evaporation rate was increased due to the wide dispersion of the spray droplets and the strong interaction between spray droplets and gas fields.

• The Journal of Engineering Geology
• /
• v.33 no.4
• /
• pp.717-724
• /
• 2023

Residual shear strength is an important parameter in landslide dynamics and may be considered the critical factor in landslide triggering. Tests were undertaken using Jumunjin sands to examine the effects of smooth and rough surfaces on ring-shear characteristics. Under dense and drained conditions, shear velocities were recorded as 0.01, 0.1, 1, 10, 50, 100 mm s^-1, with shear strength increasing with velocity and producing increasingly fine content. Particle fragmentation may thus increase landslide mobilization when the landslide body is mixed with ambient water in channelized flows.

• Journal of the Korean Society of Radiology
• /
• v.17 no.7
• /
• pp.1075-1089
• /
• 2023

Nuclear forensics is an essential part of nuclear material control and nuclear non-proliferation verification. Radiochronometry for nuclear forensics is used to estimate the timing of refinement and production of nuclear materials based on decay chain characteristics and the Bateman equation. The results of radiochronometry have uncertainties because the decay constant and number of nuclides are statistics derived from analyses or repeated experiments and involve uncertainties. The aim of this study was to develop an uncertainty calculation algorithm by performing computational simulation to overcome the limitations of the existing uncertainty calculation method for radiochronometry based on the Bateman equation. The results of the proposed uncertainty calculation algorithm were comparable to those of the existing method. The algorithm allowed for more than two generations of uncertainty calculations and mitigated the underestimation of the decay constant during the uncertainty calculation.