• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.6
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• pp.766-772
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• 2007

As XML is widely used, many researches on the XML storage and query processing have been done. But, previous works on path query processing have mainly focused on the storage and retrieval methods for a large XML document or XML documents had a same DTD. Those researches did not efficiently process partial match queries on the differently-structured document set. To resolve the problem, we suggested a new index structure using relational table. The method constructs the $B^+$-tree index using backward label paths instead of forward label paths used in previous researches for storing path information and allows for finding the label paths that match the partial match queries efficiently using it when process the queries.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.2
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• pp.89-94
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• 2005

In this paper, we propose a fuzzy PID controller of new method. There are two problems in absolute digital PID controller. First, much calculation time need for obtain the sum of data at each period. Second, this is problem need much memory because to storage every data at the before period. We use the speed type PID digital controller to improvement such problems. In the propose controller doesn't use without adjustment the crisp output error and we doesn't use nile tables in the fuzzy inference process at the forward stage fuzzifier. We inference output member ship function by using the relation and range of two variable of PID gain parameters. We can obtained desired results through the simulation and a experiment of the hydraulic servo motor control system.

• Transactions on Electrical and Electronic Materials
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• v.14 no.4
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• pp.177-181
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• 2013

In this paper, silicon solar cells are analyzed regarding power conversion efficiency by changed capacitance in the depletion region. For the capacitance control in the depletion region of silicon solar cell was applied for 10, 20, 40, 80, 160 and 320 Hz frequency band character and alternating current(AC) voltage with square wave of 0.2~1.4 V. Academically, symmetry formation of positive and negative change of the p-n junction is similar to the physical effect of capacitance. According to the experiment result, because input of square wave with alternating current(AC) voltage could be observed to changed capacitance effect by indirectly method through non-linear power conversion (Voltage-Current) output. In addition, when input alternating current(AC) voltage in the silicon solar cell, changed capacitance of depletion region with the forward bias condition and reverse bias condition gave a direct effect to the charge mobility.

• Journal of Korea Water Resources Association
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• v.54 no.7
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• pp.545-552
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• 2021

The burden of flood control on the dam under frequently flood due to climate change and especially heavy flood in 2020 year are come to the forward and increased. The objective of the study is therefore to establish the method to estimate capacity and target water level for flood control in actual dam management. Frequency matching method was applied to establish a pair of cumulative distribution function (CDF) based on daily dam inflow and discharge records. The relationship between dam storage and discharge volume represented as a percentage of inflow volume was derived and its characteristics was analyzed. As the result, the Soyanggang (45%) and Chungju Dam (39%) contributing to flood control with temporarily storing flood runoff. The method and diagram to estimate flood control capacity and target water level for flood control in the dam were established. The result of the study could be used as a supplementary data for flood control of the dam according to the rainfall prediction on the Korea Meteorological Administration.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.2
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• pp.233-246
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• 2015

Focus on Digital Fashion Image, the conceptual framework for the thesis is established from Virtuality in Digital Art. Formative characteristics and aesthetic characteristics were studied by classifying the Digital Fashion Image applied and expressed by digital media and technology. A detective research method was used for a case study. A literature study for case-by-case data was analyzed with focus on the works expressing fashion that utilized digital media and technology since the 2000s. Through this study, the Digital revolution has created the socio-cultural impact of a Virtual representation to implement technology and fashion culture that finds ways to take advantage of the image shown in a Digital Fashion Media by understanding Virtuality. The results are as follows. First, it was a re-formation of the fashion culture through the experience of virtuality with mental zone parameters between the media 'Mediation Code'. Reflect the reality of the virtual environment as represented by a cultural image of fashion brands and fashion that reset the team relationship and formed a Homo Ludens cultural code. Second, 'Interactive Exchange' acts on the exchange interaction between the method of digital technology, the human and the machine as well as the technical interoperability of network elements and techniques. This exchange is applied to fashion images that express emotion. Forming personalized fashion items and the user interactively storage that expresses the interactive exchange to forward the identity of the emotional fashion by a change in the message delivery system fashion. Third, the emphasis on intuitive artistic expression 'Synesthesia Immersion' induces a sense of immersion and excitement through the fusion of the interconnected. Enhance a visual image in fashion sensory representation and maximize a tactile and visual virtual reality involvement.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.153-165
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• 2014

Carbon dioxide capture and storage (CCS) technology is recognizing one of method responding the climate change with reduction of carbon dioxide in atmosphere. In Korea, due to its geological characteristics, sub-seabed geological $CO_2$ storage is regarded as more practical approach than on-land storage under the goal of its deployment. However, concerns on potential $CO_2$ leakage and relevant acidification issue in the marine environment can be an important subject in recently increasing sub-seabed geological $CO_2$ storage sites. In the present study effect data from literatures were collected in order to conduct an effect assessment of elevated $CO_2$ levels in marine environments using a species sensitivity distribution (SSD) various marine organisms such as microbe, crustacean, echinoderm, mollusc and fish. Results from literatures using domestic species were compared to those from foreign literatures to evaluate the reliability of the effect levels of each biological group and end-point. Ecological effect guidelines through estimating level of pH variation (${\delta}pH$) to adversely affect 5 and 50% of tested organisms, HC5 and HC50, were determined using SSD of marine organisms exposed to the $CO_2$-induced acidification. Estimated HC5 as ${\delta}pH$ of 0.137 can be used as only interim quality guideline possibly with adequate assessment factor. In the future, the current interim guideline as HC5 of ${\delta}pH$ in this study will look forward to compensate with supplement of ecotoxicological data reflecting various trophic levels and indigenous species.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.941-948
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• 2005

In the self-healing group key distribution scheme, users are capable of recovering lost group keys on their own without requesting additional transmission from the group manager, where there is no reliable network infrastructure. In this paper, we propose a new self-healing group key distribution scheme with revocation capability, which is optimal in terms of user memory storage and more efficient in terms of communication complexity than the previous results. We obtain a slightly improved result from (13) and (14) by using the new broadcasting method. In addition, we prove that our scheme has the properties of t-wise forward secrecy and t-wise backward secrecy, and extend this self-healing approach to the session key recovery scheme from a single broadcast message.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.129-137
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• 2016

In the present study we verified performance of feed-forward control algorithm using short term prediction of ship motion information by taking advantage of developed numerical simulation model of FPSO motion. Up until now, various studies have been conducted about thrust control and allocation for dynamic positioning systems maintaining positions of ships or marine structures in diverse sea environmental conditions. In the existing studies, however, the dynamic positioning systems consist of only feedback control gains using a motion of vessel derived from environmental loads such as current, wind and wave. This study addresses dynamic positioning systems which have feedforward control gain derived from forecasted value of a motion of vessel occurred by current, wind and wave force. In this study, the future motion of vessel is forecasted via Brown's Exponential Smoothing after calculating the vessel motion via a selected mathematical model, and the control force for maintaining the position and heading angle of a vessel is decided by the feedback controller and the feedforward controller using PID theory and forecasted vessel motion respectively. For the allocation of thrusts, the Lagrange Multiplier Method is exploited. By constructing a simulation code for a dynamic positioning system of FPSO, the performance of feedforward control system which has feedback controller and feedforward controller was assessed. According to the result of this study, in case of using feedforward control system, it shows smaller maximum thrust power than using conventional feedback control system.