• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.113-118
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• 2006

Recently, wireless LANs are often applied in home or office because of its various of convenience. Frequency rage of wireless LANs specified by IEEE 802.11b is at 2.4 GHz. The bluetooth, the microwave oven, and the PDA(Personal Digital Assistants) uses ,however, the same frequency band. So problems will be produced in these environments, such as multi-pass interference and system-to-system interference. These problems can be eliminated by using EM wave absorber. In this paper, we designed and fabricated EM wave absorber using Sendust, $Al(OH)_3$, and CPE. The double-layered EM wave absorber with thickness of 1.5 mm has absorption ability more than 10 dB at 2.4 GHz.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.865-868
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• 2007

Recently, wireless LANs are often applied in home or office because of its various of convenience. Frequency range of wireless LANs specified by IEEE 802.11b is at 2.4 GHz. The bluetooth, the microwave oven, and the PDA(Personal Digital Assistants) uses, however, the same frequency band. So problems will be produced in these environments, such as multi-pass interference and system-to-system interference. These problems can be eliminated by using EM wave absorber. In this paper, we designed and fabricated EM wave absorber using MnZn-Ferrite, Sendust, and CPE( Chlorinated Polyethylene). The EM wave absorber with the ratio of material (MnZn-Ferrite : Sendust : CPE = 64 : 16 : 20 wt.%) has thickness of 3.7 mm and absorption ability more than 17 dB at 2.4 GHz.

• PNF and Movement
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• v.13 no.2
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• pp.89-93
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• 2015

Purpose: This study aimed to verify the effect of integrated patterns (IPs) of PNF on individuals with malalignment using upper extremity and lower extremity patterns simultaneously. This information was then compared to the effect of bowling exercises on malalignment. The study population included individuals in their twenties with malalignment in their posture. Methods: Individuals with malalignment (40 participants in total) were divided into 2 groups based on trunk inclination and side deviation. In one group, IPs of PNF were used as interventions, while the other group used bowling exercises. This process was completed over the course of four weeks. The IP group used two patterns simultaneously: flexion-adduction-external rotation and extension-abduction-internal rotation. These patterns were used in the upper and lower extremities and were crossed diagonally. Results: The trunk inclination decreased in the IP and the bowling group. In the IP group, the degree of inclination decreased from 0.94 to 0.33. The side deviation also decreased to 1.53 (p < 0.05). In the bowling group, the two measured values decreased significantly (p < 0.05). Conclusion: Compared to the bowling exercises used in the bowling group, the results of this study indicate that the use of IPs had a significant effect on trunk inclination and side deviation for malalignment posture patients. Individuals can easily improve malalignment using IPs of PNF (for example, at home or at their office), which suggests that they are not required to seek assistance from a fitness or bowling center, which may save them time.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.963-973
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• 2021

Based on the TPB(Theory of Planned Behavior), this study explores the physical education perceived by college students by applying the causal relationship (SEM) to life sports, participation intention, and participation behavior perceived by college students in the Covid-19 environment, and to provide basic data for predicting life sports events. For this, a total of 267 people were analyzed using the mobile program "Survey Monkey" according to the sample plan from December 1, 2020 to May 1, 2020. As a result of the study, it was found that the planned behavior theory had a statistically significant positive(+) correlation with the intention to participate in physical education. The planned behavior theory showed that there was a statistically significant positive(+) correlation with the life sports participation behavior. Lastly, the intention to participate in physical sports was found to have a statistically significant positive(+) correlation with participation in physical sports.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.271-278
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• 2021

This paper is a study on the implementation of smart filter system that recognizes the external environment and automatically removes pollutants according to pollution level. Recently, the occurrence of various pollutants in indoor and outdoor space has adversely affected the human body. Especially, various fine dust generated in the atmosphere becomes worse in closed residential space or office space. Although air pollution can be temporary lowered through ventilation, it is difficult to respond to fine dust changes in real time, and such problems become serious in the space where many people reside, such as at home or industry. Therefore, it is necessary to measure the pollution level of fine dust inside the residential space in real time and to reduce the pollution of indoor ventilation through automatic ventilation with the outside. To improve these problems, this paper proposes the implementation of smart filter system for external environment recognition. The structure of smart filter system that automatically measures air quality inside and outside, removes pollutants, implements the function, and confirms the operability by manufacturing prototypes. Finally, the effectiveness of the smart filter system for solving fine dust problems was examined.

• Informatization Policy
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• v.25 no.4
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• pp.108-120
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• 2018

With the rise of the Fourth Industrial Revolution and I-Korea 4.0, both of which pursue strategies for industrial innovation and for the solution to social problems, the real estate industry needs to change in order to make effective use of available space in smart environments. The implementation of smart spaces is a promising solution for this. The smart space is defined as a good use of space, whether it be a home, office, or retail store, within a smart environment. To enhance the use of smart spaces, efficient decision-making and well-timed and accurate interaction are required. This paper proposes a smart space based on platform which takes advantage of emerging technologies for the efficient storage, processing, analysis, and utilization of big data. The platform is composed of six layers - collection, transfer, storage, service, application, and management - and offers three service frameworks: activity-based, market-based, and policy-based. Based on these smart space services, decision-makers, consumers, clients, and social network participants can make better decisions, respond more quickly, exhibit greater innovation, and develop stronger competitive advantages.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.6
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• pp.109-117
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• 2011

We can use document issuance services provided by a school, bank, hospital, company, etc. either by visiting those facilities or by simply visiting their Web sites. Services available through the Internet allow us to use the same services as we do by actually going to those facilities at home or office any time. As much as it saves us time and money, there also arises a problem of information being forged on the Internet or on a printed document. There has to be security functions to deal with the problem. This paper intends to think of the possible security threats and draw out the necessary security functions that an on-line document issuance system should have based on the CC v3.1, so that anyone can use it as reference when they evaluate or introduce the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.818-825
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• 2020

The embedded system can be defined as a special purpose system with a built-in computer, and has a wide variety of applications such as home appliances, office equipment, and weapon systems. A well-defined taxonomy in a specific field is advantageous for learning and education, however, the classification scheme for embedded systems is difficult to find. In this paper, we propose a taxonomy for embedded systems. First, the generalized structure of the embedded system was presented. And, it is divided into two parts: "firmware based" and "embedded OS based". In addition, according to the characteristics of embedded system applications, it is divided into two categories: "non-dependable" application and "dependable" application, which makes 4 planes. We describe the features of each quadrant and show that the classification is well suited by showing examples. Our taxonomy can be used to set teaching and learning methods of embedded systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1596-1602
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• 2021

Battery-operated IoT devices in IoT systems require low power consumption. In general, IoT devices enter a sleep state synchronously to reduce power consumption. A problem arises when an IoT device has to handle asynchronous user requests, as the duty cycle must be reduced to enhance response time. In this paper, we propose a new low-power-consumption scheme, called Repetitive Wake-up scheme for IoT systems of asynchronous environments such as indoor lights control. The proposed scheme can reduce power consumption by sending wake-up signals from the smartphone repetitively and by retaining the IoT device in sleep state to the smallest possible duty cycle. In the various environments with IoT devices at home or office space, we showed that the proposed scheme can reduce power consumption by up to five times compared to the existing synchronous interlocking technique.

• Journal of Information Technology Services
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• v.20 no.5
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• pp.89-104
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• 2021

Food delivery service combined with IT technology and HMR (Home Meal Replacement) are rapidly growing due to the COVID-19. Recently, the demand for salads along with HMR has increased among office workers in their 20s and 30s who are interested in health and beauty. Freshcode is a food startup with 6 years of experience that started selling salad products through O2O service. Freshcode applied for a patent for a service that collects orders from nearby areas and delivers them on the same day to a designated delivery address 'FCOSPOT' to save shipping costs. In March 2021, in recognition of the growth potential of the regular delivery service, Freshcode received an investment of 6 billion won in Series A. This study may have practical implications to early-stage startups and scale-up stage startups through a longitudinal case study on the growth of a single company. As for the research method, the lean startup methodology and lean canvas were used in the early stage of startup. In particular, the process of the build-measure and learn feedback-loop, which is the core of lean startup methodology, was applied to each major decision-making step. In the scale-up stage after 5 years, the business model canvas was used to schematize the growth as a food online O2O platform to verify continuous innovation. This case study has three main findings. First, the idea of 'FCOSPOT' was successfully implemented through the Lean Startup methodology. Second, Freshcode demonstrated the scalability of the differentiated business model of shared base delivery O2O. Third, a key factor of success was the digital integrated communication operation strategy that maximizes the experience for the created customers.