• Archives of design research
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• v.14
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• pp.87-106
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• 1996

Recent rapid development of electronic technologies and semiconductors has made it possible to perform diverse intelligent functions even in simple products. This technological sophistication, in turn, made it difficult to get required information on the usage of products by just its shape. Under these new circumstances, User-interface design became more important. However existing studies were mainly done with the emphasis of software development and focusing on the evaluation-stage after development of alternatives. This study sets the objective for developing modeling technique which can be applied to product design and the stage of concept development. At first the role of modeling was discussed to understand the nature of modeling. Then the existing techniques of modeling were reviewed for identifying advantages and limits. The review of existing modeling techniques revealed general objectives which new modeling techniques should fulfill. Based on objectives new modeling techniques were proposed. Following this new techniques, actual case of modeling a existing product were demonstrated to evaluate the validity of new technique and show the actual application. Finally findings were summarized and the limits of the study were identified.

• Fibers and Polymers
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• v.7 no.2
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• pp.129-138
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• 2006

Using a strain-controlled rheometer, the steady shear flow properties of aqueous xanthan gum solutions of different concentrations were measured over a wide range of shear rates. In this article, both the shear rate and concentration dependencies of steady shear flow behavior are reported from the experimentally obtained data. The viscous behavior is quantitatively discussed using a well-known power law type flow equation with a special emphasis on its importance in industrial processing and actual usage. In addition, several inelastic-viscoplastic flow models including a yield stress parameter are employed to make a quantitative evaluation of the steady shear flow behavior, and then the applicability of these models is also examined in detail. Finally, the elastic nature is explained with a brief comment on its practical significance. Main results obtained from this study can be summarized as follows: (1) Concentrated xanthan gum solutions exhibit a finite magnitude of yield stress. This may come from the fact that a large number of hydrogen bonds in the helix structure result in a stable configuration that can show a resistance to flow. (2) Concentrated xanthan gum solutions show a marked non-Newtonian shear-thinning behavior which is well described by a power law flow equation and may be interpreted in terms of the conformational status of the polymer molecules under the influence of shear flow. This rheological feature enhances sensory qualities in food, pharmaceutical, and cosmetic products and guarantees a high degree of mix ability, pumpability, and pourability during their processing and/or actual use. (3) The Herschel-Bulkley, Mizrahi-Berk, and Heinz-Casson models are all applicable and have equivalent ability to describe the steady shear flow behavior of concentrated xanthan gum solutions, whereas both the Bingham and Casson models do not give a good applicability. (4) Concentrated xanthan gum solutions exhibit a quite important elastic flow behavior which acts as a significant factor for many industrial applications such as food, pharmaceutical, and cosmetic manufacturing processes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.1
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• pp.41-47
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• 2012

Recently, due to the rapid rise of the international oil price, the burden of fuel oil expense is relatively increasing in a ship. And the international restriction of the greenhouse gas which was generated from the burning of fuel oil is also rapidly strengthened. Therefore, to reduce the greenhouse gas and fuel oil consumption, many shipping company adopted the low speed navigation and it was focused on the improvement of fuel consumption efficiency and the usage of alternative energy in the marine engine development field. In this paper, the fuel oil consumption according to the ship's speed was measured in the actual seas and analyzed the shop test results in the shipyard and the ship navigation data from the abstract log. And then it was proposed that the ship's economic speed was 14~15kts and the optimum rpm was 140~150 in specific sea conditions.

• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.109-120
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• 2013

As information-oriented industry has been developed and electronic devices has come to be smaller, lighter, multifunctional, and high speed, the components used to the devices need to be much high density and should have find pattern due to high integration. Also, diverse reliability problems happen as user environment is getting harsher. For this reasons, establishing and securing products and components reliability comes to key factor in company's competitiveness. It makes accelerated test important to check product reliability in fast way. Out of fine pattern failure modes, failure of Electrochemical Migration(ECM) is kind of degradation of insulation resistance by electro-chemical reaction, which it comes to be accelerated by biased voltage in high temperature and high humidity environment. In this thesis, the accelerated life test for failure caused by ECM on fine pattern substrate, $20/20{\mu}m$ pattern width/space applied by Semi Additive Process, was performed, and through this test, the investigation of failure mechanism and the life-time prediction evaluation under actual user environment was implemented. The result of accelerated test has been compared and estimated with life distribution and life stress relatively by using Minitab software and its acceleration rate was also tested. Through estimated weibull distribution, B10 life has been estimated under 95% confidence level of failure data happened in each test conditions. And the life in actual usage environment has been predicted by using generalized Eyring model considering temperature and humidity by developing Arrhenius reaction rate theory, and acceleration factors by test conditions have been calculated.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.251-257
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• 2011

When designing a ship, ergonomic considerations are crucial when minimizing a navigator's fatigue due to the burden of work, and to appropriately operate the navigational equipment for each given situation by helping the operator to understand the surroundings as well as the physical functions of the ship. However, insufficient consideration of ergonomic elements in the actual design of ship Bridges is lowering the performance of safe navigation and allows for the possibility of operation or readout errors. Consequently, these errors lead to an increase in maritime accidents. Therefore, this study conducted a usability evaluation on the importance of and the usage frequency of navigational equipment, their influence on actual navigation, and the possibility of error upon operation or readout between training ship officers, to derive an optimized layout that includes the consideration of ergonomic factors for on-Bridge navigational equipment, which are currently arranged differently according to their type or size. The optimized layout of on-Bridge navigational equipment was carried out based on the evaluation results, using the Lingo program. Through the process of optimization, revised layouts of on-Bridge navigational equipments(control and display device) were suggested, considering emergency situations(ship collision, stranding, fire and explosion, sinking, etc.) during navigation.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.198-198
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• 2016

The Citarum River Basin is the biggest river basin in West Java Province, Indonesia and it plays strategic roles in providing water for irrigation, domestic and industrial uses, and power generation, besides controlling the flood during rainy season. Flowing through seven major cities makes the river flow and water demand are vulnerable to land use change around the river. The present water resources management has involved the regulator, operator, and users in deciding an appropriate water management plan for the entire basin. The plan includes an operation plan for three reservoirs, construction or maintenance of the river channel, and water allocation for all users along the river. Following this plan, a smaller operation group will execute and evaluates the plan based on the actual flow condition. Recently, a deforestation, environment degradation, river sedimentation, a rapid growth of population and industry, also public health become new issues that should be considered in water basin planning. Facing these arising issues, a new development program named ICWRMIP was established to advance the existing management system. This program includes actions to strengthen institutional collaboration, do the restoration and conservation of the river environment, improve water quality and public health, also advance the water allocation system. At present, the water allocation plan is created annually based on a forecasted flow data and water usage prediction report. Sometimes this method causes a difficulty for the operator when the actual flow condition is not the same as the prediction. Improving existing system, a lot of water allocation studies, including a development of the database and water allocation simulation model have been placed to help stakeholders decide the suitable planning schemes. In the future, this study also tries to contribute in advancing water allocation planning by creating an optimization model which ease stakeholders discover a suitable water allocation plan for individual users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.3199-3218
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• 2019

Location-based services (LBSs) have become popular in recent years due to the ever-increasing usage of smart mobile devices and mobile applications through networks. Although LBS application provides great benefits to mobile users, it also raises a sever privacy concern of users due to the untrusted service providers. In the lack of privacy enhancing mechanisms, most applications of the LBS may discourage the user's acceptance of location services in general, and endanger the user's privacy in particular. Therefore, it is a great interest to discuss on the recent privacy-preserving mechanisms in LBSs. Many existing location-privacy protection-mechanisms (LPPMs) make great efforts to increase the attacker's uncertainty on the user's actual whereabouts by generating a multiple of fake-locations together with user's actual positions. In this survey, we present a study and analysis of existing LPPMs and the state-of-art privacy measures in service quality aware LBS applications. We first study the general architecture of privacy qualification system for LBSs by surveying the existing framework and outlining its main feature components. We then give an overview of the basic privacy requirements to be considered in the design and evaluation of LPPMs. Furthermore, we discuss the classification and countermeasure solutions of existing LPPMs for mitigating the current LBS privacy protection challenges. These classifications include anonymization, obfuscation, and an encryption-based technique, as well as the combination of them is called a hybrid mechanism. Finally, we discuss several open issues and research challenges based on the latest progresses for on-going LBS and location privacy research.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.161-167
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• 2019

Recently, demand forecasting techniques have been actively studied due to interest in stable power supply with surging power demand, and increase in spread of smart meters that enable real-time power measurement. In this study, we proceeded the deep learning prediction model experiments which learns actual measured power usage data of home and outputs the forecasting result. And we proceeded pre-processing with moving average method. The predicted value made by the model is evaluated with the actual measured data. Through this forecasting, it is possible to lower the power supply reserve ratio and reduce the waste of the unused power. In this paper, we conducted experiments on three types of networks: Multi Layer Perceptron (MLP), Recurrent Neural Network (RNN), and Long Short Term Memory (LSTM) and we evaluate the results of each scheme. Evaluation is conducted with following method: MSE(Mean Squared Error) method and MAE(Mean Absolute Error).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.85-92
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• 2021

Ambient Air Vaporizer (AAV) is an essential facility in the process of generating natural gas that uses air in the atmosphere as a medium for heat exchange to vaporize liquid natural gas into gas-state gas. AAV is more economical and eco-friendly in that it uses less energy compared to the previously used Submerged vaporizer (SMV) and Open-rack vaporizer (ORV). However, AAV is not often applied to actual processes because it is heavily affected by external environments such as atmospheric temperature and humidity. With insufficient operational experience and facility operations that rely on the intuition of the operator, the actual operation of AAV is very inefficient. To address these challenges, this paper proposes an artificial intelligence-based model that can intelligent AAV operations based on operational big data. The proposed artificial intelligence model is used deep neural networks, and the superiority of the artificial intelligence model is verified through multiple regression analysis and comparison. In this paper, the proposed model simulates based on data collected from real-world processes and compared to existing data, showing a 48.8% decrease in power usage compared to previous data. The techniques proposed in this paper can be used to improve the energy efficiency of the current natural gas generation process, and can be applied to other processes in the future.

• Journal of Hospice and Palliative Care
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• v.23 no.4
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• pp.212-227
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• 2020

Purpose: This study presents the process of designing workbooks for advance care planning appropriate for the Korean cultural setting and describes actual case studies. Methods: This study focused on single inductive case studies of the utilization of an advance care planning workbook and recruited individual participants. Results: The workbook for adolescents contained six sessions and the workbook for children contained seven sessions. The workbook sessions led to four major discoveries: 1) considering the Korean cultural context, discussions on life and death must be held indirectly; 2) the role of the counselor as a supporter is crucial for the workbook to be effective; 3) the workbook must be accessible regardless of the seriousness of the illness; and 4) patients must be able to make their own choice between the workbook versions for children and adolescents. Six facilitating factors improved engagement: 1) the role of the counselor as a supporter; 2) building trust with the patient; 3) affirming freedom of expression on topics the patient wished to avoid talking about; 4) having discussions on what private information to keep secret and to whom the information can be disclosed; 5) discovering and regularly discussing relevant topics; and 6) regular communication and information-sharing with the patient's medical service providers. Conclusion: It is necessary to build on actual case studies regarding workbooks for children and adolescents in order to expand the usage of these workbooks to all relevant medical institutions in Korea.