• International Journal of Naval Architecture and Ocean Engineering
• /
• v.5 no.2
• /
• pp.246-262
• /
• 2013

With increases in international oil prices, the proportion of fuel cost to the operational costs of a ship is currently increasing. To reduce fuel cost, a method for determining an economical route for a ship based on the acquisition of the sea state and the estimation of fuel consumption is proposed. The proposed method consists of three items. The first item is to acquire the sea state information in real time. The second item is to estimate the fuel consumption of a ship according to the sea state. The last item is to find an economical route for minimal fuel consumption based on the previous two items. To evaluate the applicability of the proposed method, it was applied to routing problems in various ocean areas. The result shows that the proposed method can yield economical ship routes that minimize fuel consumption. The results of this study can contribute to energy savings for environmentally friendly ships.

• International Journal of Control, Automation, and Systems
• /
• v.4 no.5
• /
• pp.653-659
• /
• 2006

The design of $H_2$-optimal control with regional pole assignment via state feedback in linear time-invariant systems is investigated. The aim is to find a state feedback controller such that the closed-loop system has the desired eigenvalues lying in some desired stable regions and attenuates the disturbance between the output vector and the disturbance vector. Based on a proposed result of parametric eigenstructure assignment via state feedback in linear systems, the considered $H_2$-optimal control problem is changed into a minimization problem with certain constraints, and a simple and effective algorithm is proposed for this considered problem. A numerical example and its simulation results show the simplicity and effectiveness of this proposed algorithm.

• International Journal of Control, Automation, and Systems
• /
• v.5 no.3
• /
• pp.343-348
• /
• 2007

This paper presents an adaptive controller for the compensation of state-dependent disturbance with unknown amplitude in a digital servo motor system. The state-dependent disturbance is caused by friction and eccentricity between the wheel axis and the motor driver of a mobile robot servo system. The proposed control scheme guarantees an asymptotical stability for both the velocity and position regulation. An experimental result shows the effectiveness of the adaptive disturbance compensator for wheeled-mobile robot in a low velocity diffusion tracking. A comparative experimental study with a simple PI controller is presented.

• International Journal of Automotive Technology
• /
• v.7 no.1
• /
• pp.101-107
• /
• 2006

The force and moment simulation of a steady-state rolling tire taking the effect of tread pattern into account is described using a steady-state transport method with ABAQUS. Tread meshes can not fully consider a tread pattern because detailed tread meshes are not allowed in the steady-state transport method. Therefore, the tread elements are modeled to have orthotropic property instead of isotropic property. The force and moment simulation has been carried out for the cases of both isotropic and orthotropic properties of tread elements. Both cases of simulation results are then compared with the experimental results. It is verified that the orthotropic case is in a better agreement with the experimental result than the isotropic case. Angle effects of tread pattern have been studied by changing the orientation angle of orthotropic property of tread. It is shown that the groove angle in the tread shoulder region has a more effect on force and moment of a tire than that in the tread center region.

• Journal of the Korean Home Economics Association
• /
• v.38 no.12
• /
• pp.111-129
• /
• 2000

The purpose of this study is to investigate the level of consumer instantly impulse buying in cuber market user. Also this study analyzes causal effect on consumer instantly impulse purchasing by demographic and social, place and promotion, consumer emotion state, and consumer internal and psychological variables. The data had been collected from on-line research method with 1,034, as using cuber market. The major statistical methods used for data analysis are frequency, percentile, mean, factor analysis, multiple regression analysis, Pearson's correlation analysis, and path analysis. The result of causal effect analysis were as follows; First, the variables affecting possession oriented materialism were sex and age. Second, the variables affecting self-control were sex, income, account of credit card, and instantly state of mind. Third, variables directly affecting instantly impulse purchasing were serif employed, banner advertisement, experience of cuber shopping, shopping mall pattern, instantly state of mind, purpose of shopping, happiness and success oriented materialism, and self-control. Also sex, income account of credit card, and instantly state of mind emerge to indirectly effect via self-control. Especially, the variables of success oriented materialism and instantly state of mind influenced on the highest of relative variables in consumer instantly impulse purchasing.

• International Journal of Computer Science & Network Security
• /
• v.22 no.4
• /
• pp.67-72
• /
• 2022

The main purpose of the study is to analyze the main aspects of state regulation of the banking business in the context of social and digital transformation. One of the key elements of the functioning of the economy of any country are banks that ensure the redistribution of financial resources and stimulate economic growth. However, the banking sector, like other activities, is dynamic and depends on the pace of development and forms of technological progress that affect the forms and types of information and digital technologies, as well as the globalization and remoteness of banking services. Accordingly, the need for effective implementation of the latest technologies becomes relevant, which will not only help increase consumer satisfaction with the banking product, but also ensure the development of the country's financial sector. As a result of the study, trends in the development of state regulation of the banking sector in the digital economy were identified.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.27 no.4
• /
• pp.332-338
• /
• 2022

This study proposes a battery state-of-health estimation method by applying a feature extraction technique. The technique that can improve estimation performance is the process of identifying and extracting meaningful data. To apply a data-driven-based aging state estimation method to batteries, health indicators are used as training data. However, limitations occur in extracting health indicators from charge/discharge cycles. This study proposes a deep-learning-based battery state-of-health estimation method that applies feature extraction techniques to compensate for this problem. According to the performance evaluation result of the proposed method, it has a low estimation error of 0.3887% based on an absolute error evaluation method.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1997.04a
• /
• pp.43-51
• /
• 1997

Steady and unsteady numerical simulations are conducted for the experiments performed to investigate the ram accelerator flow field by using the expansion tube facility in Stanford University. Navier-Stokes equations for chemically reacting flows are analyzed by fully implicit and time accurate numerical methods with Jachimowski's detailed chemistry model for hydrogen-air combustion involving 9 species and 19 reaction steps. Although the steady state assumption shows a good agreement with the experimental schlieren and OH PLIF images for the case of $2H_2$+$O_2$+$17N_2$, it fails in reproducing the combustion region behind the shock intersection point shown in the case of $2H_2$+$O_2$+$12N_2$, mixture. Therefore, an unsteady numerical simulation is conducted for this case and the result shows all the detailed flow stabilization process. The experimental result is revealed to be an instantaneous result during the flow stabilization process. The combustion behind the shock intersection point is the result of a normal detonation formed by the intersection of strong oblique shocks that exist at early stage of the stabilization process. At final stage, the combustion region behind the shock intersection point disappears and the steady state result is retained. The time required for stabilization of the reacting flow in the model ram accelerator is found to be very long in comparison with the experimental test time.

• The Korean Journal of Food And Nutrition
• /
• v.23 no.4
• /
• pp.492-500
• /
• 2010

This study conducted a questionnaire survey of 482 male and female second graders in middle schools located in Cheongju, Chungcheongbukdo. This study lays its purpose on establishing the nutrition facts labeling system by understanding eating habits and analyzing the actual state of reading nutrition facts labels and degrees of understanding them among middle school students, and helping them to engage in right food purchasing activities and through it result in developing sound eating habits by providing them with basic material to be employed to actively utilize nutrition facts for choosing and buying healthy foods. As a result of surveying regarding the actual state of reading food labels, regarding degrees of recognition of food labels, it was revealed that 91.1% of female students recognized them, while 42.1% of male students did not recognize them, indicating lower levels of recognition among the male group. Regarding reasons for not checking food labels, 49.2% indicated habitual purchasing, followed by poor contents in the label(20.2%), ununderstandable contents(17.7%), and the lower reliability of the contents(6.9%). As a result of surveying regarding the actual state of reading nutrition facts labels, in recognition of nutrition facts labels, female rather than male students showed higher degrees of recognition, and degrees of recognition were found to differ according to parents' total income and mothers' educational attainments.

• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.7
• /
• pp.688-698
• /
• 2012

This paper deals with ROLSO (Reduced Order Luenberger State Observer) design to prevent jackknifing phenomenon of articulated vehicles consisting of the tractor and semi-trailer by using GPS. In addition, by applying the regulator system using ROLSO feedback system, simulation's result presents that articulated vehicle's states are stabilized than the human's PR time (Preception Response time) rapidly. This simulation verifies that the automatic control of articulated vehicle's can be applied for the accident prevention for the time that the driver is unable to manage with the sudden accident. For this simulation, by using the equation of planar motion, the modeling of the articulated vehicle was performed. This modeling was expressed in the state space model. And FOLSO (Full Order Luenberger State Observer), ROLSO were designed by using the state space model of an articulated vehicle's dynamics.