• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.37-40
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• 2016

Performance enhancement of organic light-emitting diodes (OLEDs) is investigated in a device structure of ITO/TPD/Alq₃/LiF/Al and ITO/TPD/Alq₃/BCP/LiF/Al. Here, bathocuproine (BCP) is used as an electron-transport layer. Current density-voltage-luminance characteristics of the OLEDs show that the performance of the device is better with BCP layer than without BCP layer. The current density, luminance, luminous efficiency, and external-quantum efficiency are improved by approximately 22%, 50%, 2%, and 18%, respectively. Since the BCP layer lowers the electron energy barrier, electron transport is facilitated and the movement of hole is blocked as the applied voltage increases. This results in an increased recombination rate of holes and electrons.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.409-414
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• 2003

A multi-span bridge model that is fixed in longitudinal direction at a single pier can be very vulnerable to the earthquake ground motion in longitudinal direction. If the seismic load exceeds the capacity of the pier, it can be severely damaged. However, such incident can be prevented if piers of movable support share the seismic load as setting up seismic load transmitting device. This study is performed to investigate seismic performance of continuous bridge model with seismic load transmitting devices which is proposed newly. It is found that continuous bridge model system with device is more effective about displacement control and seismic performance.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.537-544
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• 2006

In this study, performance level evaluation tests have been actually performed on laminated rubber seismic isolation bearings (LRB) made in Korea. To provide basic data for setting up fabrication criteria and performance evaluation criteria three real scale LRB were tested and the test results were analysised. Accordingly, a large capacity test device has been designed and manufactured to implement the tests. The device selected for evaluation is a circular LRB actually applied in bridges. Evaluation tests were conducted using full-scale LRB with diameter of 851mm in the rubber part and total height of 215mm of which the effective horizontal stiffness and equivalent damping ratio have been measured during the experiments.

• Journal of the Society of Disaster Information
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• v.11 no.1
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• pp.45-54
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• 2015

In the case of railway facilities in cities such as a railway station or a bridge, the significance of design for reducing vibration and noise is getting more significant. The vibration control solution is in need especially for an elevated railway station to block vibration of a train and secondary noise effectively. Even though a vertical vibration isolation device is able to be applied effectively to railway facilities such as elevated railway stations which transfer vibration directly from a train to a structure, the development of the vertical device is much slower than a horizontal vibration isolation device. In this paper, a vibration isolation device using wedge type friction material which is currently developing to reduce train-induced vibration effectively is introduced and test results for verification of dynamic performance is also presented. The vibration test on a concrete structure equipped with the developed vibration isolation device is conducted through which the isolation performance and dynamic properties are verified and needs for improving the performance of the device is identified.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.240-248
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• 2016

As a new technical approach, the achievement of an eco-environmental leisure boat with a photovoltaic system is attempted by simultaneously actuating nine photovoltaic solar panels, in association with an applied sail control system by use of wind. In this approach, the photovoltaic system consists of a solar module, an inverter, a battery, and relevant components, while the sail control device is equipped with a sail up/down and mast-turning instrument. Furthermore, this research conducts a performance evaluation of the manufactured prototype and acquires the purposed quantity value and the development purpose items. The significant items-sail up/down speed (seconds) and mast turning angle (degrees)-are evaluated during the performance test. In the process of the performance evaluation, a wind direction sensitivity of 90% and a maximum instant charging power of 900 W were also obtained. In addition, the maximum sail time is evaluated in order to acquire the optimum quantity.

• Journal of the Ergonomics Society of Korea
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• v.32 no.2
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• pp.179-187
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• 2013

Objective: The purpose of this study is to extract GOMS manual operator, except for an experiment with participants. Background: The GOMS model has advantage of rapid modeling which is suitable for the environment of technology development which has a short life cycle products with a fast pace. The GOMS model was originally designed for desktop environment so that it is not adequate for implementing into the latest HCI environment such as small touch screen device. Therefore, this research proposed GOMS manual operator extraction methodology which is excluded experimental method. And flick Gesture was selected to explain application of proposed methodology to extract new operator. Method: Divide into start to final step of hand gesture needed to extract as an operator through gesture task analysis. Then apply the original GOMS operator to each similar step of gesture and modify the operator for implementation stage based on existing Fitts' law research. Steps that are required to move are modified based on the Fitts' law developed in touch screen device. Finally, new operator can be derived from using these stages and a validation experiment, performed to verify the validity of new operator and methodology by comparing human performance. Results: The average movement times of the participants' performance and the operator which is extracted in case study are not different significantly. Also the average of movement times of each type of view study is not different significantly. Conclusion: In conclusion, the result of the proposed methodology for extracting new operator is similar to the result of the experiment with their participants. Furthermore the GOMS model included the operator by the proposed methodology in this research could be applied successfully to predict the user's performance. Application: Using this methodology could be applied to develop new finger gesture in the touch screen. Also this proposed methodology could be applied to evaluate the usability of certain system rapidly including the new finger gesture performance.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.35-42
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• 2013

In this paper, the analog performance of FinFET structure was estimated by extracting the DC/AC characteristics of the 22 nm process FinFET structures with different layout considering spacer and SEG using 3D device simulator, Sentaurus. Based on the analysis results, layout methods to enhance the analog performance of multi-fin FinFET structures are proposed. By adding the spacer and SEG structures, the drive current of 1-fin FinFET increases. However, the unity gain frequency, $f_T$, reduces by 19.4 % due to the increase in the total capacitance caused by the added spacer. If the process element is not included in multi-fin FinFET, replacing 1-finger with 2-finger structure brings approximately 10 % of analog performance improvement. Considering the process factors, we propose methods to maximize the analog performance by optimizing the interconnect and gate structures.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.454-468
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• 2015

The purpose of this study is to investigate the relationship between product attributes of smart device and user acceptance of technology. Moreover, the authors examined mediating effect of utilitarian and hedonic motivation between product attributes and user acceptance. Previous researches focused on user attitude and behavior intention of new technology based on Technology Acceptance Model(TAM). However, differently from previous researches, which are focused on user attitude like perceived usefulness and perceived ease of use, this research emphasized the relationship product attributes such as product functionality, design, and convenience and user motivation both utilitarian(effort expectancy and performance expectancy) and hedonic motivation(perceived enjoyment) according to UTAUT model. The results shows that 3 motivation variables(effort expectancy, performance expectancy, and perceived enjoyment) have positive impacts on user acceptance intention of smart device. product design has positive relationship to perceived enjoyment and product convenience has positive relationship to both effort and performance expectancy. Furthermore, 3 motivation variables play a full mediation between product attributes and user acceptance intention of new technology. However, product functionality has no relationship to both effort and performance expectancy. Research contribution, implications, and further research directions are discussed at the end of the paper.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.6
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• pp.45-53
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• 2010

The unseating failure of bridges, which is one of the most severe types of damage leading to the loss of transportation function, should be avoided in earthquakes. As a measure of prevention of unseating failure resulting from the failure of bearings, bearing-protection devices are frequently used. They are installed beside the bearings and protect the bearings by resisting a seismic load transmitted from the superstructure. In order to show appropriate seismic performance, the strength of anchors as well as of device bodies should be confirmed. In Korea, they have been installed only according to the design provided by device agents, because a proper design method for the anchors has not been established. In this study the performance of bearing-protection devices with various heights of concrete bed blocks has been investigated experimentally, and a proper design method has been proposed to secure seismic performance.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.245.2-245.2
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• 2013

Solution processed organic photovoltaic devices have relatively less attention compared to polymer photovoltaic devices even though they have high possibility to be developed because they have both advantages of polymer and organic, such as solution processable, no synthetic batch dependence of photovoltaic performance, high purity and high charge carrier mobility as well as relatively high efficiency (~7%). In addition, solution processed organic photovoltaic devices have an advantage of easiness to study the relationship between the molecular structure and photovoltaic performance due to its simple structure. In this work, five isoindigo based low band gap donor-acceptor-donor (D-A-D) small molecules with different electron donating strength were synthesized for investigating the relationship between the molecular structure and photovoltaic performance, especially, investigating the effects of different electron donating effect of donor group in isoindigo backbone to photovoltaic device performance. The variation of electron donating strength of donor group strongly affected the optical, thermal, electrochemical and photovoltaic device performances of isoindigo organic materials. The highest power conversion efficiency of ~3.2% was realized in bulk heterojuction photovoltaic device consisted of the ID3T as donor and PC70BM as acceptor. This work demonstrates the great potential of isoindigo moieties as electron deficient units as well as guideline for synthesis of donor-acceptor-donor (D-A-D) small molecules for realizing highly efficient solution processed organic photovoltaic devices.