• Journal of the Korea Society of Computer and Information
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• v.24 no.2
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• pp.57-66
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• 2019

This paper compared the performance with an overview of channel equalization techniques used in high-speed serial transceivers, including the homogeneous architecture and associated components for the GHz interconnect of backplane and cable channels. It also used the MATLAB tool to present system analysis and simulation results for continuous time equivalent structures. In the case of conventional continuous equalization, high frequency deficits occur due to the use of a comparator that is difficult to implement as well as the low speed limit. In this paper, the channel equalization technique based on the power spectrum analysis of clocks was used to compensate for the frequency loss, and the application of the TX+Channel and TX+Equalizer filters enabled the measurement of attenuation and equivalence without comparators. The application of blender and band-pass filters at high speeds also showed significant effectiveness.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.20-24
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• 2017

For process improvement and cutting down on expenses in solar cell industry, it is necessary to improve recycling process of wafer manufacturing. In this research, a study is introduced to develop classifier which is for recycling of abrasive. First of all, recycling process of wafer manufacturing is analyzed. And then, 3 steps of experiments such as oil removal, impurities removal and classification were executed. For the classification of slurry, a classifier is designed and manufactured. From experiments, it is verified that ultra sound vibration and flux are very important factors for classification. By experiencing the recycling processes and making devices, the technique can be initiated industry if needed such as decreasing waste and cutting down on expenses.

• Journal of the Semiconductor & Display Technology
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• v.18 no.2
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• pp.17-22
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• 2019

The method of electrical discharge machining (EDM), one of the processing methods based on non-traditional manufacturing procedures, is gaining increased popularity, since it does not require cutting tools and allows machining involving hard, brittle, thin and complex geometry. This present investigation details the determination of optimum process parameter to attain the better machining performance in EDM of AISI 4340 steel with graphite as a tool electrode. The experimental combinations are planned and analyzed by Taguchi's design of experiments approach. To predict the optimal condition, the experiments are conducted by using Taguchi's L27 orthogonal array. The influence of process variables such as discharge current, pulse on and pulse off time, voltage and spark speed were investigated to control the various desired performance measures such as surface roughness. Analysis of Variance (ANOVA) has to be performed to know the magnitude of each factor. Investigations indicate that the surface roughness is strongly depend on pulsed current.

• Current Optics and Photonics
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• v.3 no.5
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• pp.374-381
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• 2019

This study examined a method for designing the optical cavity of a non-dispersive infrared gas detector. The infrared gas detector requires an optical cavity design to lengthen the ray path. However, the optical cavity with multiple reflecting surfaces has off-axis aberration due to the characteristics of the reflecting optical system. The rays were parallelized by using the off-axis parabolic mirror to easily increase the ray path and eliminate off-axis aberration so that the rays are admitted to the effective area of the infrared detector uniformly. A prototype of an infrared gas detector was produced with the designed optical cavity to confirm the performance.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1023-1035
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• 2022

In the current situation where clearly the ship officer is avoiding boarding, the purpose of this study is to investigate the satisfaction of onboard training in shipping companies during the COVID-19 situation and to suggest plans to improve onboard training. Furthermore, by improving satisfaction, students of maritime university can improve their career awareness as a ship officer in the future. The survey was conducted with the cadets of Mokpo Maritime University after completion of onboard training in shipping companies. The questionnaire contains seven factors: education administration, education contents, officer, facility, education ef ect, education satisfaction and career awareness. The survey analysis results indicated that the satisfaction with education administration and education effect was relatively low, and the satisfaction differed by gender and vessel type. In addition, hypothesis verification revealed that the education contents did not have a positive effect on education satisfaction and career awareness. Furthermore, a great correlation existed between education satisfaction and career awareness. We suggested that education and promotion must be improved before onboard training. In addition, the officer must be educated on the method to teach cadets and establish a training plan such that the officer can systematically guide the cadets with an educator mindset.

• Journal of Practical Engineering Education
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• v.11 no.1
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• pp.61-73
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• 2019

Recently the Korean life-long occupational skill development system is undergoing rapid change and innovation on the basis of NCS (National Competency Standards). In order for the NCS-based occupational training system to be successfully established, it is required to be accepted and applied in the higher education. Universities, however, hesitate to adopt NCS-based contracted education programs of the work-and-study cooperative system due to low relevance of university education to industrial needs and absence of the reference operation model for the NCS-based contracted education programs considering Korean small companies' particular needs. This study aims to develop and apply a reference operation model for NCS-based contracted education programs of the university-linked work-and-study parallel system, focusing on the Department of Mechanical Design Engineering of College of Work and Study in Parallel, Koreatech. In addition, several operational guidelines are suggested within the framework of current law and regulations for successful diffusion of the NCS-based reference operation model. The results of this study are expected to contribute to nation-wide proliferation of NCS-based contracted education programs in the higher education and motivating companies and universities to participate in the work-and-study parallel initiatives.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.305-320
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• 2021

Due to COVID-19, the education and training environment in vocational competency development has changed significantly. In vocational education and training, where the proportion of face-to-face training is more extensive than in other areas of education, some training courses had no choice but to be converted to online. This study presents a distance training system plan for non-contact vocational training by analyzing the learner's non-contact learning experiences. Non-face-to-face education experiences were investigated for learners of private vocational training institutions, universities, and public higher vocational training institutions. The main contents of the survey were to analyze the non-face-to-face learning experiences of these learners for the educational environment and educational purposes. Based on the results of the learners' non-face-to-face learning experiences, a draft of a remote training system construction plan for non-face-to-face education was composed, and a Delphi study was conducted on the draft non-face-to-face remote training system. A method for establishing a distance training system including non-face-to-face teaching and learning strategies, learning and operation support was proposed with these results.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.3
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• pp.59-65
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• 2011

According to the trends of electronic package to be smaller, thinner and more integrative, Flip Chip Ball Grid Array (FCBGA) become more used for mobile phone. However, the flip chip necessarily generate the heat by the electrical resistance and generated heat is increased due to reduced distribution area of the heat in accordance with the miniaturization trend of the package. Thermal issues can result in problems of devices that are sensitive to temperature and stress. Then the heat can generate problems to the system. In this paper, in order to improve the thermal issues of FCBGA, thermal characteristics of FCBGA was analyzed qualitatively by using the general heat transfer module of Comsol 3.5a and In order to solve thermal issues, flip chip with new micro structure is proposed by the simulation. and also by comparing existing model and analyzing variables such as pitch, height of the pattern and shape of the heat spreader, the improvement of heat dissipation characteristics about 18% was confirmed.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.3
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• pp.49-56
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• 2012

Recently, by the trends of electronic package to be smaller, thinner and more integrative, fine bump is required. but It can result in the electrical short by reduced cross-section of UBM and diameter of bump. Especially, the formation of IMCs and KV can have a significant affects about electrical and mechanical properties. In this paper, we analyzed the thermal deformation of flip-chip bump by using FEM. Through Thermal Cycling Test (TCT) of flip-chip package, We analyzed the properties of the thermal deformation. and We confirmed that the thermal deformation of the bump can have a significant impact on the driving system. So we selected IMCs thickness and bump diameter as variable which is expected to have implications for characteristics of thermal deformation. and we performed analysis of temperature, thermal stress and thermal deformation. Then we investigated the cause of the IMC's effects.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.37-42
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• 2018

Recently, there have been many studies on the IoT environment in which the sensors attached to the equipment automatically transmit and process the site information in real time through the network to control the equipment. The core of such a system is a network for data transmission and reception, and a wired network with wide transmission distance is a priority. However, in the case of a wired network, there is a problem that the time and cost consumed to configure the communication is higher than that of the wireless. In this paper, we propose LPWA - based wireless data transmission system using LPWA and BLE communication to solve this problem. The proposed system collects data from equipment through BLE and transmits data to the server using LPWA. Experimental results show that the spreading factor of maximum length of LPWA is 8, and the minimum length is 9.