• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.137-147
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• 2013

It is essential to understand the hydraulic characteristics of rivers for increasing flood-control capacity and operating hydraulic structures efficiently. Multi-dimensional models can be the proper measures to obtain the detailed information on the hydraulic characteristics of rivers. But huge amount of data and time-consuming work have been the obstacle for applying multi-dimensional models. In this study, simulation technique with multi-dimensional model(EFDC), coupled with COSFIM and FLDWAV, has been developed and applied to the real river system for verification. Developed technique can offers spatial and grid unit information as well as line and section unit information from 1-D modeling. It is considered that the coupling simulation technique can provide useful hydraulic information for river management and treatment.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.241-251
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• 2014

Mobile messenger services (MMSs), such as Kakaotalk, Wetalk, Line, and Whatsapp, are gaining popularity worldwide because of communicating with other people without any cost. We examined key antecedents of user loyalty to understand user's decision-making process in the MMS environment. To capture a long-term relationship with service providers, we posit relational commitment and user satisfaction as key predictors of user loyalty. Moreover, the effects of perceived usefulness, perceived enjoyment, and corporate image on user's decision-making processes were examined. The proposed model was tested by applying partial least squares to data from 220 experienced Kakaotalk users. The findings of this study found that both relational commitment and user satisfaction play an important role in enhancing user loyalty in the MMS context. The analysis results indicate that corporate image influences relational commitment and user loyalty through user satisfaction. The analysis results help MMS providers establish management or marketing strategies to effectively improve user loyalty.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.11
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• pp.88-95
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• 1998

This paper is the result of constructing information processing system such as living creatures' brain based on artificial life techniques. The living things are best information processing system in themselves. One individual is developed from a generative cell. And a species of this individual has adapted itself to the environment through evolution. In this paper, we propose a new method of designing neural networks using biological inspired developmental and evolutionary concept. Ontogeny of organism is embodied in cellular automata(CA) and phylogeny of species is realized by evolutionary algorithms(EAs). We call 'Evolving Cellular Automata Neural Systems' as ECANSI. The connection among cells is determined by the rule of cellular automata. In order to obtain the best neural networks in given environment, we evolve the arragemetn of initial cells. The cell, that is a neuron of neural networks, is modeled on chaotic neuron with firing or rest state like biological neuron. A final output of network is measured by frequency of firing state. The effectiveness of the proposed scheme is verified by applying it to Exclusive-OR and parity problem.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.1-5
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• 2009

A new pixel circuit for Active Matrix Organic Light Emitting Diodes (AMOLEDs), based on the polycrystalline silicon thin film transistors (Poly-Si TFTs), was proposed and verified by SMART SPICE simulation. One driving and six switching TFTs and one storage capacitor were used to improve display image uniformity without any additional control signal line. The proposed pixel circuit compensates an inevitable threshold voltage variation of Poly-Si TFTs and also compensates the degradation of OLED at low power supply voltage($V_{DD}$). The simulation results show that the proposed pixel circuit successfully compensates the variation of OLED driving current within 0.8% compared with 20% of the conventional pixel circuit.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.853-858
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• 2019

One of the methods which can enhance the efficiency of railroad network is construction of interconnection branch line for several route to share one railway. In Korea, this method already has been implemented or excuted as project level. This study suggests a network design model and a solution algorithm to choice most proper site to construction it and determine the priority of branch lines which can be considered in planning level, not project level. The model is a non-linear optimization program which minimize total cost-construction cost, operating cost and passengers' travel cost. The decision variables are a binary variable to explain whether construction or not and its direction and a integer variable of the frequencies of travel routes. The solution algorithm-problem solution and route choice and also the result of implementation for example network are suggested. This result can be more advanced after application in real network and calibration of parameters.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.3
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• pp.49-61
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• 2017

Due to Proliferation of Mobile Devices, the Global Mobile Application (App) Market is Set to Continue its Impressive Growth Trajectory. However, like other Digital Contents, Prevalent Piracy of Smartphone Apps has Become One of the Major Obstacles to the Growth of the Newborn App Industry. The Objective of this Study is to Examine and Better Understand the Effects of Factors Which has been Known to Influence PC Software Piracy. A Research Model Explaining the Impact of Various Factors to Smartphone App Piracy Attitude and Intention is Constructed Based on Theories of Ethical Behavior. A Survey of College Students was Conducted to Test the Research Model. Findings Show that PC Software Piracy Habit and Attitude have Significant Effects on Smartphone Piracy Attitude and Intention. Beliefs Concerning Judicial and Performance Risks Due to Piracy have Little Effects on Smartphone App Piracy Attitude.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.949-963
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• 2017

This study present an efficient way of operating drainage pump station as part of nonstructural measures for reducing urban flood damage. The water level in the drainage pump station was forecast using Neuro-Fuzzy and then operation rule of the drainage pump station was determined applying the genetic algorithm method based on the predicted inner water level. In order to reflect the topographical characteristics of the drainage area when constructing the Neuro-Fuzzy model, the model considering spatial parameters was developed. Also, the model was applied a penalty type of genetic algorithm so as to prevent repeated stops and operations while lowering my highest water level. The applicability of the development model for the five drainage pump stations in the Mapo drainage area was verified. It is considered to be able to effectively manage urban drainage facilities in the development of these operating rules.

• Journal of Korea Port Economic Association
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• v.33 no.3
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• pp.53-68
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• 2017

The purpose of this study is to develop a new Korean container freight index by applying weights based on the global trade volume. To achieve this, it was decided to determine the conditions such as establishment of routes and regions, weighting of trade volumes which based on prior research and expert advice. Based on this, the individual index and regional index and composite index were calculated, and then reliability and statistical significance of the index was verified through correlation analysis and Granger causality analyses. This study suggest the following findings, through the development of the Korean container freight index. Firstly, Korean freight index reflects the overall market situation and can be used as a benchmark for determining the conditions of each market, consisting of criteria of region and routes. Secondly, it is possible to reflect the market conditions in which actual freight differences exist, since it has developed separate indexes for export and import routes. Finally, The composite index is the only index that reflects not only exports and imports but also 27 individual routes based on Busan, which is the most comprehensive indicator of the korean container freight market.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.4
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• pp.332-337
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• 2018

This paper presents the design optimization of fuel sensor location used to measure remained fuel amount in aircraft conformal fuel tank. The conformal fuel tank is utilized to expand the mission range in airplane, and the sensor location is a critical design variable determining the measurement accuracy. In this work, the sensor location is optimized to minimize unmeasurable fuel amount due to non-contact between fuel and sensor. The simplified model is prepared from the conformal fuel tank CATIA model, and the unmeasurable fuel amount is calculated. Then, the optimization is performed using MATLAB optimization solver. The optimized sensor location is validated by comparing with the location obtained using parametric study.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.245-254
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• 2015

This research aims to look into correlation between Korea's childbirth promotion policy caused from women's maternity leave and economic activity. For the purpose, 300 surveys were distributed to mothers using postnatal care centers located in Seoul. Listed postnatal care centers such as Babe Glory, Shinsegae, Happy, Miznomall and out of 260, 222 surveys were selected for the research. Several advanced studies regarding child birth promotion policy backed up by current government and related domestic and overseas documents were used as reference. Decisive factors including social insurance, tax, cost for child birth and rearing service, social culture were derived as trait elements for child birth promotion. Mentioned factors along with economic activity by childbearing women were used when setting up the research model and hypothesis. Relation with material leave was employed as parameter for this study of which purpose lies in empirical analysis and investigation.