• Journal of Korean Society for Quality Management
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• v.48 no.1
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• pp.171-186
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• 2020

Purpose: The purpose of this study is conducting of predictive models that considered multicollinearity of independent variables in order to carry out more efficient and reliable predictions about differential pressure in seawater reverse osmosis. Methods: The main variables of each RO system are extracted through factor analysis. Common variables are derived through comparison of RO system # 1 and RO system # 2. In order to carry out the prediction modeling about the differential pressure, which is the target variable, we constructed the prediction model reflecting the regression analysis, the artificial neural network, and the support vector machine in R package, and figured out the superiority of the model by comparing RMSE. Results: The number of factors extracted from factor analysis of RO system #1 and RO system #2 is same. And the value of variability(% Var) increased as step proceeds according to the analysis procedure. As a result of deriving the average RMSE of the models, the overall prediction of the SVM was superior to the other models. Conclusion: This study is meaningful in that it has been conducting a demonstration study of considering the multicollinearity of independent variables. Before establishing a predictive model for a target variable, it would be more accurate predictive model if the relevant variables are derived and reflected.

• Journal of Auto-vehicle Safety Association
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• v.5 no.2
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• pp.24-31
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• 2013

This paper describes a coordinated control algorithm for rear-side collision avoidance. In order to assist driver actively and increase driver's safety, the proposed coordinated control algorithm is designed to combine lateral control using a steering torque overlay by Motor Driven Power Steering (MDPS) and differential braking by Vehicle Stability Control (VSC). The main objective of a combined control strategy is twofold. The one is to prevent the collision between the subject vehicle and approaching vehicle in the adjacent lanes. The other is to limit actuator's control inputs and vehicle dynamics to safe values for the assurance of the driver's comfort. In order to achieve these goals, the Lyapunov theory and LMI optimization methods has been employed. The proposed coordinated control algorithm for rear-side collision avoidance has been evaluated via simulation using CarSim and MATLAB/Simulink.

• The KIPS Transactions:PartB
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• v.11B no.2
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• pp.207-212
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• 2004

This paper presents a reinforcement learning framework for stock trading systems. Trading system parameters are optimized by Q-learning algorithm and neural networks are adopted for value approximation. In this framework, cooperative multiple agents are used to efficiently integrate global trend prediction and local trading strategy for obtaining better trading performance. Agents Communicate With Others Sharing training episodes and learned policies, while keeping the overall scheme of conventional Q-learning. Experimental results on KOSPI 200 show that a trading system based on the proposed framework outperforms the market average and makes appreciable profits. Furthermore, in view of risk management, the system is superior to a system trained by supervised learning.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.8
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• pp.327-334
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• 2013

Today's network traffic has become extremely complex and diverse since the speed of network became faster and a variety of application services appear. Moreover, many applications appear and disappear fast and continuously. However, the current traffic classification system does not give much attention to this dynamic change of applications. In this paper, we propose an application awareness system in order to solve this problem. The application awareness system can provide the information, such as the usage trend of conventional applications and the emergence of new applications by recognizing the application name in a rapidly changing network environment. In order to recognize the application name, the Host field of HTTP protocol has been utilized. The proposed mechanism consists of two steps. First, the system generates the candidates of application name by extracting the domain name from the Host field in HTTP packet. Second, the administrator confirms the name afterward. The validity of the proposed system has been proved through the experiments in campus network.

• The KIPS Transactions:PartC
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• v.17C no.2
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• pp.173-180
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• 2010

Information technology is being applied to the development of ubiquitous healthcare system, which provides both efficient patient care and convenient treatment regardless of patient's location. However, the increasing number of users and medical information give rise to the problem of user management and the infringement of privacy. In order to address this problem we propose a user access scheme based on the RBAC (Role Based Access Control) model. The preceding trust management model for Grid security, FAS(Federation Agent Server), was analyzed and extended to provide supplementary functions for role-based access control in u-Healthcare system. The RBAC model provides efficient user management and access control, but very vulnerable in case when one with valid role tries to leak confidential inner medical information. In order to resolve this problem, a RBAC-WS (Work Status with RBAC) model has been additionally developed which allows only qualified staffs to access the system while on duty. Th proposed RBAC and RBAC-WS model have been merged together and applied to the PACS (Picture Archiving and Communication System).

• Journal of Advanced Navigation Technology
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• v.23 no.3
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• pp.221-227
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• 2019

In this paper, interacting multiple model (IMM) filter was designed that guarantees a stable navigation performance even in the unstable satellite navigation position. In order to design IMM filter in INS / GPS integrated navigation system, sub filter of the IMM filter is defined as Kalman filter. In the IMM filter configuration, two subfilters are determined. Each Kalman filter defines the six-teenth state composed of position, velocity, attitude, and sensor error from the INS error equation and the states additionally derived in case of the coloured measurement noise. In order to verify the performance of the proposed filter, we compared the performance how the filter works in the presence of arbitrary error in GPS navigation solution. The Monte Carlo simulation was performed 100 times and the results were compared with the root mean square(RMS). The results show that the proposed method is stable against errors and show fast convergence.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.47-53
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• 2022

With the recent development of defense technology, various aircraft armaments/equipments are being developed. Among them, cruise guided weapons(missile) for launching aircraft can be installed on aircraft aftersecuring reliability and safety through varioustests. In order to avoid collision with aircraft, missile separated from aircraft must release restraint of wing at the specified time, control wing in the specified direction. In order to confirm this, a test system that can control MIL-STD-1760 according to safety separation procedure and verify release performance is required. test system needs a function to check circuit for release of restraints and a function to check driving performance by controlling MIL-STD-1760. In addition, test system should be simulate environment separated from aircraft. This paper presented a testsystemthat can verify circuit and driving performance mounted on missile according to the safety separation procedure, and it was confirmed that it was normally separated from aircraft through flight tests.

• Land and Housing Review
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• v.13 no.2
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• pp.125-139
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• 2022

For construction companies to become competitive innovative, cost management as well as process improvement are required. Activity-based costing (ABC), which uses cost information to support long-term decision-making, is a tool that enhances a company's competitiveness. In this study, we compare and analyze tradition-based costing (TBC) and ABC to confirm the adequacy of performance-based costing. In addition, we will empirically examine the relationship between the impact of the reward system using ABC on employee satisfaction and involvement. In research results, the influence of the reward system on employee involvement appeared in the order of intrinsic reward (𝛽 = 0.338) and extrinsic reward (𝛽 = 0.308). In addition, the reward system showed positive (+) effects on employee satisfaction, with influence appearing in the order of intrinsic reward (𝛽 = 0.360) and extrinsic reward (𝛽 = 0.337). And employee satisfaction (𝛽 = 0.225) had a positive effect on involvement. We were able to confirm that it is necessary to build a reward system consisting of intrinsic and extrinsic rewards to increase employee satisfaction and involvement.

• Analyses & Alternatives
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• v.2 no.2
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• pp.67-91
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• 2018

This study scrutinizes the necessity and cases of the public and pension cooperation and tries to present the way of construction of information infrastructure for the pension systems suitable for Korea. The developed countries have recently been focusing on strengthening the multi-pillar pension system, while pension education and information services have emerged as an important element of the pension cooperation. The frame of the multi-pillar-pension system in Korea has already been constructed, but it is not substantial. Especially bad information on the pension system has seriously hindered the consolidation of the pension system. In order to solve this problem, we analyzed cases of public-private cooperation systems in Iceland, New Zealand, Netherlands, and Sweden. In order to build a basic infrastructure for construction pension cooperation in Korea, it is necessary to promote information exchange and cooperation among pension organizations and to improve the pension portal of NPS 'My Pension'. In addition, this study suggests establishing an association of private and public pension schemes, which manages the integrated information and education of pension systems.

• Journal of Wind Energy
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• v.14 no.2
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• pp.26-33
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• 2023

In this study, the global response characteristics of floater and mooring for floating offshore wind turbine with a detachable mooring system are performed. Global motion and structural response result extracted from the coupled motion analysis of 10MW DTU floating offshore wind turbine with detachable mooring system modeled by high-order boundary element model and finite element mesh, were used to study the characteristics of tension on mooring lines subjected to three different types of ocean loads. Breaking limit of mooring line characterized by wind, current and wave load has a major effect on the distribution of mooring tension found in time domain analysis. Based on the numerical results of coupled motion analysis, governing equation for calculating the motion response of a floater under ocean loads, and excitation force and surge motion and tension respectively are presented using excursion curve. It is found that the response of floater is reliable and accurate for calculating the tension distributions along the mooring lines under complex loadings. This means that the minimun breaking limit of mooring system satisfied a design criteria at ultimate ocean environmental loading condtions.