• KNOM Review
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• v.22 no.2
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• pp.29-38
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• 2019

The rapid growth of IoT (Internet of Things) owing to the advancement and spread of technologies such as wireless networks, communication modules, sensors, smart terminals, etc. enables the development of new services in diverse public and private sectors. In particular, research on IoT technology and its applications has increased in the field of science. To establish an IoT infrastructure in this field, KREONET launched the wireless IoT network, called ScienceLoRa, based on low power wide area network (LPWAN). ScienceLoRa aims to collect a variety of data from sensors and utilize and analyze the collected data for research in a variety of scientific fields. In this article, the authors present the concept, current status, applications and future plans of ScienceLoRa.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.103-110
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• 2009

We are witnessing rapid increase of the number of wireless devices available today such as cell phones, PDAs, Wibro enabled devices. Because of the inherent limitation of the bandwidth available for wireless channels, broadcast systems have attracted the attention of the research community. The main problem in this area is to develop an efficient broadcast program. In this paper, we propose a dynamic broadcast method that overcomes the limitations of static broadcast programs. It optimizes the scheduling based on the probabilistic model of user requests. We show that dynamic broadcast system can indeed improve the quality of service using user requests. This paper extends our previous work in [1] to include more thorough explanation of the proposed methodology and diverse performance evaluation models.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.49-49
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• 2020

하천 보 상류영역에서 발생하는 박리 흐름을 분석하기 위해 실험수로에 하천보 모형을 설치하고, 보 주변에서 발생하는 흐름 구조를 입자 영상 유속계(PIV)로 이용하여 정밀하게 측정하였다. 본 연구에 사용된 보는 하천 설계기준을 따른, 전방 수직벽과 하류 경사램프가 있는 유한한 마루 길이 보이다. 실험 조건은 보 상·하류부 수심으로 인한 4가지 흐름(Hydraulic jump, Plunging jet, Surface wave, Surface jet)을 기반으로 설정하여 수리조건에 따른 유속 특성을 규명하였다. 실험에서 측정한 수직-수평방향 평균 유속·유선도를 분석한 결과, 보 전방의 하부에서 재순환 흐름이 관측되었고, 역방향 흐름도 이 지역에서 발견되었다. 유속 편차의 제곱 평균(Root Mean Square) 흐름장에서 보 전방과 재순환 흐름 영역에 불안전한 흐름이 강하게 발견되었다. 역방향 흐름은 박리 흐름에서 발견되는 주요 특성으로, 역방향 흐름의 전체 면적을 매 관측마다 측정하여 이를 분석한 결과, 재순환 흐름의 면적은 오른쪽으로 기울어진 분포를 가지고, 항상 0보다 큰 값을 가지는 것으로 나타났다. 재순환 면적에 따른 흐름 특성은 역방향 흐름 면적에 대한 조건부 평균을 이용하여 파악했는데, 조건부 평균의 구간은 재순환 흐름의 중심에서 지배적인 주기값을 이용했다. 역방향 흐름이 작은 영역에선, 보 상류의 흐름이 재순환 흐름으로 말려들어가는 열린 박리흐름이 나타나며, 역방향 흐름이 큰 경우에는 재순환 영역의 흐름은 보 상류의 흐름과 분리되는 닫힌 박리흐름이 발생하였다. 역방향 흐름이 가장 큰 경우, 보 전방의 박리흐름은 보의 상단을 넘는 것으로 관찰되었다. 이러한 결과를 통해 보 마루에서 발생하는 박리흐름이 보 전방에 박리흐름에 영향을 미치는 것으로 파악되었다. 조건부 평균된 역방향 흐름의 면적과 박리 지점(separation point)의 관계를 분석한 결과, 역방향 흐름의 오른쪽으로 기울어진 분포와 대규모 흐름 방출 현상이 관측되었다. 박리 지점의 위치와 수리 매개변수의 관계를 분석한 결과, 상류의 수심 증가에 따라 증가하는 경향이 나타났다.

• Convergence Security Journal
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• v.22 no.4
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• pp.119-127
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• 2022

A movie information program has a positive effect on the viewer's intention to watch the movie by providing an indirect experience of the movie based on trust. In order to increase the effectiveness of a movie information program, a data service that provides the additional information on the movies introduced in a movie information program has been studied. However, since the study limited the data service to one movie information program, it was difficult to apply it to the actual environment of general cable broadcasting companies or satellite broadcasting companies that transmit multiple movie information programs. Therefore, this study expanded the existing research limited to one movie information program to provide additional information of several movie information programs. This study is meaningful in that it suggests a data service that can be operated in the realistic environment of a broadcaster that actually transmits several movie information programs.

• Convergence Security Journal
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• v.23 no.2
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• pp.37-45
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• 2023

Cyber deception technology plays a crucial role in monitoring attacker activities and detecting new types of attacks. However, along with the advancements in deception technology, the development of Anti-honeypot technology has allowed attackers who recognize the deceptive environment to either cease their activities or exploit the environment in reverse. Currently, deception technology is unable to identify or respond to such situations. In this study, we propose a predictive model using Markov chain analysis to determine the identification of attackers who infiltrate deceptive environments. The proposed model for deception status determination is the first attempt of its kind and is expected to overcome the limitations of existing deception-based attacker analysis, which does not consider attackers who identify the deceptive environment. The classification model proposed in this study demonstrated a high accuracy rate of 97.5% in identifying and categorizing attackers operating in deceptive environments. By predicting the identification of an attacker's deceptive environment, it is anticipated that this model can provide refined data for numerous studies analyzing deceptive environment intrusions.

• Smart Media Journal
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• v.12 no.9
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• pp.134-141
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• 2023

In this paper, we propose a ToF-Stereo fusion sensor system for 3D space scanning that increases the recognition rate of 3D objects, guarantees object detection quality, and is robust to the environment. The ToF-Stereo sensor fusion system uses a method of fusing the sensing values of the ToF sensor and the Stereo RGB sensor, and even if one sensor does not operate, the other sensor can be used to continuously detect an object. Since the quality of the ToF sensor and the Stereo RGB sensor varies depending on the sensing distance, sensing resolution, light reflectivity, and illuminance, a module that can adjust the function of the sensor based on reliability estimation is placed. The ToF-Stereo sensor fusion system combines the sensing values of the ToF sensor and the Stereo RGB sensor, estimates the reliability, and adjusts the function of the sensor according to the reliability to fuse the two sensing values, thereby improving the quality of the 3D space scan.

• Tunnel and Underground Space
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• v.34 no.4
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• pp.267-282
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• 2024

This study aims to develop a wireless communication system for long-term monitoring of high-level radioactive waste disposal facilities. Conventional wired sensors can lead to a deterioration in buffer quality and management difficulties due to the use of cables for power supply and data transmission. This study proposes the adoption of a wireless communication system and compares the received signal strengths within bentonite using modules such as WiFi, ZigBee, and LoRa. Increases in dry density of bentonite and distance between transceivers led to reduced received signal strength. Additionally, using the low-frequency band exhibited less signal attenuation. Based on these findings, a conceptual design for a wireless network-based THM integrated sensor system was proposed. Results of this study can be used as foundational data for long-term monitoring of disposal facility.

• Journal of Nutrition and Health
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• v.52 no.1
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• pp.90-103
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• 2019

Purpose: This study examined the relationship of the nutrition of rice and the positive evaluation of the rice-based meal with the food consumption habits, physical and emotional health status, and learning efficacy of 601 middle and high school students in Jeonju area. Methods: The participants were divided into two groups using cluster analysis in that the participants belonging to the upper groups had a center score of 46.86 (n = 348), while the people belonging to the lower group had a center score of 36.89 (n = 253). Statistical differences were tested for all the relationships between the physical and emotional health symptoms and learning efficacy between the groups at the ${\alpha}=0.05$ level. Results: Significant differences in the physical self-evaluated symptoms were observed in all five items in each cluster (p < 0.05). In the case of the emotional health status, nine out of 10 items showed significant differences between the groups. Similarly, significant differences in all five items in learning efficacy questionnaire were noted (p < 0.05). Positive attitudes of the parents toward having breakfast also showed significant differences among the groups. Conclusion: The nutrition of rice and a positive evaluation of the rice-based meals significantly affect the physical and emotional health status and learning efficacy of juveniles. These findings can be used as baseline information for promoting nutrition education, particularly rice-based breakfast.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.453-463
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• 2008

The missing child problem is no more a personal problem. It became a social problem that all parents must consider. To this, this study applies USN/RFID technology integrated with GIS for the prevention of missing child. Although RFID is not designed for location sensing, but now it is regarded as a device to facilitate real time location awareness. Such advantages of RFID can be integrated with 4S(GIS/GPS/LBS/GNSS) achieving much synergy effects. In order to prevent kidnapping and missing child, it is necessary to provide a missing child preventing system using a ubiquitous computing system. Therefore, the missing child preventing system has been developed using high-tech such as RFID, GPS network, CCTV, and mobile communication. The effectiveness of the missing child prevention system can be improved through an accurate location tracking technology. This study propose and test a location sensing system using the active RFID tags. This study verifies technical applied service, and presents a system configuration model. Finally, this paper confirms missing child prevention system utilization possibility.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.736-743
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• 2016

In accordance with the trend of higher speed and automation, the Train Control System is building on the technology of control methods using radio in the technology of exchanging information by wire, toward a wireless communication method that will be applied using LTE-R radio communication technology with $4^{th}$ generation LTE mobile communication a $2^{nd}$ generation GSM-R. Therefore, a standard specification suitable for the Korea Radio based Train Control System-2(below KRTCS-2) for the 350km/h class using wireless communication is created; a prototype based on the standard specification is installed on a high-speed train and is installed on a test section(Ik san-Jeong eup) on the Honam high speed line to ensure the reliability and safety of the standard specifications, which are verified through various performance tests. In the future, the standard specification that has been established as a national railway standard, and the standard specifications will be commercialized by applying the train control system to conventional and High speed railway lines.