• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.173-178
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• 2019

Recently, the types and amount of data generated, collected, and measured in IoT such as smart home, security, and factory are increasing. The technologies for IoT service include sensor devices to measure desired data, embedded software to control the devices such as signal processing, wireless network protocol to transmit and receive the measured data, and big data and AI-based analysis. In this paper, we focused on developing a gateway for interfacing heterogeneous sensor network protocols that are used in various IoT devices and propose a heterogeneous network interface IoT gateway. We utilized a OpenWrt-based wireless routers and used 6LoWAN stack for IP-based communication via BLE and IEEE 802.15.4 adapters. We developed a software to convert Z-Wave and LoRa packets into IP packet using our Python-based middleware. We expect the IoT gateway to be used as an effective device for collecting IoT big data.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.41-45
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• 2018

We have simulated the process induced warpage for panel level package using finite element method. Silicon chips of $5{\times}5mm^2$ were redistributed on $122.4{\times}93.6mm^2$ size panel and the total number of redistributed chips was 221. The warpage at each process step, for example, (1) EMC molding, (2) attachment of detach core, (3) heating, (4) removal of a carrier, and (5) cooling was simulated using ANSYS and the effects of detach core and carrier materials on the warpage were investigated. The warpage behaved complexly depending on the materials for the detach core and carrier. However, glass carrier showed the lower warpage than FR4 carrier regardless of detach core material, and the minimum warpage was observed when the glass was used for the detach core and carrier at the same time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.166-172
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• 2019

A case study was performed in order to develop well-designed of thin plate door impact beam. The conventional impact beam was consisted of steel-pipe welded two brackets on the both side, which causes low productivity and high cost. In order to overcome those disadvantage, it is necessary to develop a new type of door impact; thin plate impact beam. The thin plate impact beam was not needed a welding procedure, which can lead low cost and high productivity. In order to maximally resist from an external force, the cross-section design should be well designed. 6 different cross-section design were proposed based on engineer's experience. Three point bending test was simulated those 6 different impact beam and compared the reaction forces. Among them, one case was chosen and redesigned for detail design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.600-606
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• 2018

A class D fire or combustible metal fire is characterized by the presence of burning metals. Only certain metals or metal compounds are flammable, including sodium and lithium. General fire extinguishing agents, such as dry chemical powder, water-based fire extinguish agents, and carbon dioxide, cannot be used in class D fires. This is because these agents cause adverse reactions or are ineffective. In addition, the amount of usage of combustible metals is increasing due to continuous development of the semiconductor and fuel cell industries. Despite this, Korea does not have standards and laws related to combustible metal fires. This paper suggests directions of the class D fire management policies to reduce the class D fire risk and impact by analyzing the standards and laws related to class D fires and combustible metal fire cases. The factors to make laws on class D fire prevention and response systems, and management system of dry sand were determined. These results may be used to help reduce the risk of class D fires and improve the response abilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.507-513
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• 2021

This study examined the final stop position and posture of both vehicles, the damaged part of the vehicle, the road surface, the specifications of the vehicle, and the angle of impact, centering on the case of a collision in which no surface trace was found. As a result of the simulation, the impact velocity of an SM5 and Lexus was 131 km/h and 74 km/h, respectively, and the impact angle of the SM5 and Lexus was 0.91° and -161.07°, respectively. The cause of the accident was that the SM5 passed through the intersection exceeding the maximum speed limit of 61 km/h and entered the Lexus' left turn lane. Lexus collided during the evacuation to avoid the collision. The collision trajectory error rate of the simulation was approximately 1.4%. Of the subjective experience of accident investigators, the collision dynamics and vehicle engineering aspects and simulations were actively utilized to provide close-to-fact cause identification.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.591-595
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• 2020

Intensive pulsed light (IPL) technique enables energy to be transferred to a target substance in a short time per millisecond at room temperature under an ambient atmosphere. Due to the growing interest in flashlights with excellent functionality among various technologies, light-sintering research on metal particles using IPL has been carried out representatively. Recently, examples of the application of IPL to various material synthesis have been reported. In the present article, various strategies using IPL including the manufacture of flexible electrodes and the synthesis of metal-organic frameworks were discussed. In particular, the process of improving oxidation resistance and electrical conductivity of electrodes, and also the metal-organic framework synthesis from metal surface were explained in detail. We envision that the review article can be of great help to researchers who investigate electrode manufacturing and material synthesis using IPL.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.31-36
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• 2021

Stress is a common risk factor for health and is associated with the endocrine gland and immune system. Studies on the association between stress and biochemical factors have been conducted worldwide, but studies on the association have been rare in South Korea. Therefore, the aims of this study are to analyze the relationship of stress with demographic information and biochemical factors for domestic adults and derive risk factors for stress. For data analysis, stress and normal groups were analyzed using binary logistic regression. In both men and women, age and average daily sleep time during the weekday were highly associated with stress, and the depression score (Patient Health Questionnaire-9) was also highly related with stress. In women, white blood cell levels were highly associated with stress, and in men, red blood cell levels were highly related with stress. These findings will contribute to the prevention of stress and the national health in the future.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.51-58
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• 2021

Women are reported to have increased risk of metabolic syndrome after menopause. Nevertheless, there is a lack of study on the convergent association between breast-feeding, bone mineral density(BMD) and metabolic syndrome due to women's childbirth. In this study, the data of 939 elderly women using raw data from the fifth Korean National Health and Nutrition Examination Survey(KNHANES V-1 and 2) in 2010 and 2011 were analyzed. The correlation between breast-feeding children, BMD and metabolic syndrome was analyzed by dividing them into three groups based on the number of breast-feeding children. As a result of the analysis, no specific association was found between risk factors of metabolic syndrome and BMD according to the increase in the number of breast-feeding children after adjustment for confounders. However, elderly women with a large number of breast-feeding children showed a significant association with more risk factors of metabolic syndrome. These findings can be used as a basic material for the prevention and diagnosis of metabolic syndrome and health care in elderly women.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.1
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• pp.62-68
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• 2022

Due to medical and economic development, various treatment methods are being studied to restore or maintain beautiful and healthy teeth. In particular, interest in aesthetic treatment procedures such as prosthetic treatment and whitening to restore tooth loss is increasing. One of the important things in the field of prosthetics and esthetic treatment is to determine the correct color of teeth because harmony with natural teeth is an important factor in determining the perfection of esthetic prostheses. This study is about the development of a colorimetry application for tooth colorimetry using a smartphone camera. The colorimetry application UI was designed, the colorimetry algorithm was derived and the application was implemented, and the validity of the application was verified through testing the implemented application.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.623-628
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• 2021

The paid knowledge platforms market is growing rapidly due to the constant demand for high-quality knowledge and a change in the positive perception of paid contents. Among them, the growth of paid knowledge platforms in China is overwhelming. The various paid knowledge platforms have emerged in China over the years, and Zhihu occupies the largest share among them. There have been some studies on paid knowledge platforms in China, but studies centered on Zhihu were relatively insufficient, so I conducted the research on Zhihu. In this paper, the development status of China's paid knowledge platform was investigated, the functions provided to users based on the menu configuration of the Zhihu app were analyzed and the business model of Zhihu was explored. In addition, the features of Zhihu were analyzed. It is expected that this paper will be an important data for research on paid knowledge platform.