• Journal of the Korea Society for Simulation
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• v.23 no.4
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• pp.203-210
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• 2014

This study proposes adaptive decision making method having feed-back structure of regression and simulation models to support the quick decision making of production managers by managing and integrating the mutual relationship among historical data. For that, from historical data that have extracted and accumulated from each process, we first selected major constraint resources that are used as independent variables in regression model. The regression model is designed by using the dependent variables (objectives) that defined above by managers and independent variables selected in previous step and simulation model that are composed of constraint resources is designed. In process of simulation run, we obtain the multiple feasible solutions (alternatives) by using meta-heuristic method. Each solution is substituted by regression equation and we found the optimal solution that is minimum of difference between values obtained by regression model and simulation results. The optimal solution is delivered and incorporated to production site and current operation results from production site is used to generate new regression model after that time.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.587-596
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• 2008

For Wireless internet service in Metropolitan area, optimum location selection for base station and cell planning are critical process in determining service coverage by accurate prediction of Wave Propagation Characteristics. Due to different kinds of characteristics in service area such as lay of land, natural feature and material, height and width of artificially made building, it has a great impact on the transmission and distance recovery of wireless network service. Therefore, these facts may cause substantial barriers in predicting & analyzing the expected level of service quality and providing it to subscribers. In this thesis, we have simulated the process to improve quality and coverage of the service by adjusting the location of Base station and the antenna angle that influence the service after the basic location of base station is selected according to the wave prediction model. Based on this simulations test, we have demonstrated the results in which subscribers would get higher quality of wireless internet service along with bigger coverage and the improved quality in the same service coverage area through optimization process of base station.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.533-538
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• 2005

Due to rapidly inc Due to rapidly Increase the number of vehicles, the number of vehicle passed over the traffic capacity which is allowable on each road. In order to disperse the traffic in the congestion area, ITS related techniques have been studied advancing. However, the cost of setting up and managing In is considerable to recently improve the problem or In, various traffic analysis technique are problem using low cost RFID. In this paper, the method of RFID-Reader location selection, which is a core technique to analyze traffic amount and traffic context is proposal. In order to systematically utilize traffic related road information, GIS is used for the proposal method. In addition, a rule-based model using O/D data that is the important information for selection the location of traffic observation.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.52-59
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• 2016

For almost of concrete structures by placing in cold weather, it is very important that the selection of curing method at early aged construction stage. The Exothermic curing method with hot wire and rapid hardening cement is used mostly to prevent the initial cracks and the strength decrease. Most of the construction sites, however, have not been applied to the optimal curing method caused by the simple approaches and the empirical judgements. Therefore, this paper has proposed a evaluation algorithm of the exothermic curing method for representing heating temperature, period, position of hot wire by analyzing the transient heat transfer solution. This has been implemented, moreover, using an object oriented programming language to develop structural analysis system taking account risk parameters. This system is composed of input module, database module, database store module, analysis module, and result generation module. Linkage interface between the central database and each of the related module is implemented by the visual c# concept. Graphic user interface and the relational database table are supported for user's convenience.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.271-273
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• 2006

Because effect of value elevation is great as it is fast that construction VE is enforcement, VE at the design phase is more and more important more than construction process phase. But, is exerting negative impact for construction process phase by various problem that happen at design phase, and is causing discord to between project partners. Therefore, quality security in design phase is important first of all. Hereupon, this study emphasized that need VE at the design phase of extension plan forward more and more because achieved process that derive conceptional estimation by quantitative value calculating value index (V) through provision of design function point (F) and LCC expense (C) by comparison method of construction and chooses optimum method of construction through VE/LCC analysis example in improvement of soft soil ground method choice process of design phase.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.654-658
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• 2006

To solve some problems that reveals in the exiting stickiness problem of the housetop, the housetop finishing impact layer can be displaced by the existing concrete block. By doing in this way, this need is rising that the excess cost should be reduced and the materials should be recycled in repairing. According to the above, this study is going to suggest the basic data on building and using of the dry process method by estimating and analyzing a overall determinate quantity through the experiment on the insulation performance among the capacity items on the outside insulation waterproof dry process suggested. In addition, choosing the building method according to the use, the peculiar property and the importance of the building can be possible by analyzing the defect causes happening in the rooftop insulation and waterproof, suggesting the better method and classifying the most proper choosing methods for the need of the building according to the importance of the main factors.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.166-174
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• 2015

This study examined combustion characteristics by selecting the fuel which have a different physical properties compared to gasoline in order to examine the effects of vehicle performance and environment depending on the physical properties. The experiment examined the combustion characteristic in the optimum ignition timing according to the physical properties change and the lean burn by performing control about ignition timing and air-fuel ratio for each fuel, and it was also evaluated the exhaust gas according to the experiment. We used a single-cylinder engine for the experiment, and tested for gasoline properties change by selecting a fake fuel that beyond the fuel quality standards in 석대법. As a result, in the case of the selected fuel showed a difference in Octane and distillation characteristics, vapor pressure and it was also found to unstable combustion, and leads to a large amount of harmful exhaust gas.

• Journal of Navigation and Port Research
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• v.41 no.4
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• pp.181-188
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• 2017

In the existing ship sales market, prices determined based on the prices of similar ship types that recently traded. ince the 2008 financial crisis, ship prices have fluctuated, and ship price criteria have become ever more necessary to the imminent value of the ship. Therefore, this research used the hedonic price model to estimate imminent values of ships. In this study, the influence on ship prices was analyzed by the value of each characteristic and an estimated functional formula was. Out of the four models suggested by the hedonic price model, an optimal model was selected with variance inflation factors and a stepwise selection. For this, the influence of determinants of ship prices was analyzed based on actually traded ships and characteristic data. The selected model s the Log-Line model; as a result of regression analysis, eight variables, including DWT, Age, Market Value, Short-Term Charter, Long-Term Charter, Enbloc, Special Survey Due and Builder were to affect the ship price model. This model is expected to be useful for objective and balanced ship price evaluation.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.57-65
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• 2002

The Electrical Power System (EPS) shall supply required power to maintain spacecraft and payload during the mission. The EPS sizing are based on space environment, satellite mission and lifetime, and allocated budgets. The type of the primary and secondary power is determined according to satellite design-level and allocated subsystem budgets. The design of EPS has closely related to system and others' subsystems design. To supply the sufficient power to the satellite, the implementation of the larger power source and energy storage is impossible actually. And there will be some problems of the attitude control of the satellite, the handling power capability of the electronic boxes, and launch vehicle selection caused by EPS oversizing. Also, the thermal control is not easy in the space by extra power. And the maintenance of the satellite within the specific orbit from orbit-drag is a big design burden of the thruster. So the various technologies have been developed to optimize the EPS sizing and to operate the power system efficiently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.37-47
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• 2009

When H.264 encoded video streams are transmitted over wireless network, packet loss is unavoidable. Responding on this environment, we propose methods to recover missed motion vector in the decoder: At first, A candidate vector set for missing macroblock is estimated from high correlation coefficient of neighboring motion vectors and missing block vectors the algorithm clusters candidate vectors through distances amongst motion vectors of neighboring blocks. Then the optimal candidate vector is determined by the median value of the clustered motion vector set. In next stage, from the candidate vector set, the final candidate vector of missing block is determined it has minimum distortion value considering directions of neighboring pixels' boundary. Test results showed that the proposed algorithm decreases the candidate motion vectors $23{\sim}61%$ and reduces $3{\sim}4sec$ on average processing(decoding) time comparing the existing H.264 codec. The PSNR, in terms of visual quality is similar to existing methods.