• Journal of the Korean Institute of Navigation
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• v.22 no.1
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• pp.1-13
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• 1998

Radiobeacons that carry corrections for global satellite navigation systems are currently being planned or installed in many countries. In early 1996, it was begun to send DGPS correction message from a marine radiobeacon station located in Changgi Got Lighthouse. It was the first test broadcast of DGPS correction data based on medium frequency of marine radiobeacon where transmission power and rate are 300W and 100bps respectively in Korea. However, there has not been any scientific study on the characteristic of the accuracy of a marine radiobeacon/DGPS. Accordingly, this paper investigates the accuracy of the system, which is currently operating in 310kHz. To do this , the real time differential correction in RTCM data was collected in an implemented system. And then the accuracy was analyzed related to the coverge of the radiobeacon/DGPS. As a result, it is verified that the differential positioning accuracy using the marine radiobeacon is sufficient to ensure the safety of marine activities around the coast of Korea.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.563-564
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• 2018

최근 차량 네트워크에서 포그 컴퓨팅 기능을 적용하는 새로운 연구가 진행 중이다. 특히, 최근 개발 중인 차량 포그 컴퓨팅 기술은 교통 정보를 실시간으로 수집하여 빠른 처리가 가능하며 이를 장법을 통해 안정된 차량 및 교통 서비스를 제공할 수 있다. 이런 차량 포그 컴퓨팅 기술은 교통 정보 수집, 운전 정보 제공, 스마트 교통 통제 및 도로 안전 메시지 등의 정보를 차량에 빠르게 전달할 수 있다. 본 논문에서는 차량 포그 컴퓨팅 기술을 리뷰하고 교차로 환경에서 차량 포그 컴퓨팅 기반 안전 메시지 전달을 위한 교통 시스템을 제안한다. 특히, 제안하는 기법은 대기 시간에 민감한 안전 메시지를 빠르게 전송할 수 있는 장점을 가지고 있다.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.184-190
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• 2010

In this paper, a remote submersion warning system based on multi-mode optical fiber(MMF) sensors and a wireless sensor network(WSN) are proposed. To improve the reliability and stability of the sensors, the dual optical fiber sensors combined to the optical coupler are demonstrated. A slave zigbee as a wireless sensor module was used as a platform to monitor and record the signal from the MMF sensors and then transmits these information to a master zigbee wirelessly. The monitoring system running the $LabVIEW^{(R)}$ software was connected to the internet to support the short message service(SMS) through extensible markup language(XML) web service. No matter where the managers are, they can always receive the real-time remote-monitoring data for safety check.

• International Journal of Contents
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• v.9 no.3
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• pp.29-34
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• 2013

This study attempted to compare usability of auditory interfaces, which is a comprehensive concept that includes safety, utility, effectiveness, and efficiency, in personal computing environments: verbal messages (speech sounds), earcons (musical sounds), and auditory icons (natural sounds). This study hypothesized that verbal messages would offer higher usability than earcons and auditory icons, since the verbal messages are easy to interpret and understand based on semiotic process. In this study, usability was measured by a set of seven items: ability to inform what the program is doing, relevance to visual interfaces, degree of stimulation, degree of understandability, perceived time pressure, clearness of sound outputs, and degrees of satisfaction. Through the experimental research, the results showed that verbal messages provided the highest level of usability. On the contrary, auditory icons showed the lowest level of usability, as they require users to establish new coding schemes, and thus demand more mental effort from users.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1970-1976
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• 2008

Since Daegu subway station fire killed 192 citizens in 2003, the demands about safety MRT operation has been increased. Also, the studies and patents for MRT Surveillance are increasing. The related law and system are improving, too. This study suggests the solution for digital surveillance system that has the functions for restricted zone surveillance, the harmful gas and fire surveillance and abnormal behavior surveillance by comparing and analyzing the surveillance systems of advanced countries (United states, Hongkong, Japan etc). Then, we suggest UMS(Unified Message Service) system and image storing system for effective report and management.

• Electronics and Telecommunications Trends
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• v.38 no.2
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• pp.12-25
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• 2023

Positioning, navigation, and timing information has become a key element in the national core infrastructure and for emerging technologies, such as autonomous driving, lunar exploration, financial systems, and drones. Therefore, the provision of that information by navigation satellite systems is becoming increasingly important. Existing systems such as GPS (Global Positioning System), GLONASS (GLObal NAvigation Satellite System), and BDS (BeiDou Navigation Satellite System) also provide augmentation, safety-of-life, search & rescue and short message communication and authentication services to increase their competitiveness. Those services and the signals generated for their provision have their own purpose and requirements. This article presents an overview of existing or planned satellite navigation satellite system services and signals, aiming to help understand their current status.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.49-56
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• 2011

One of the most important VANET applications is providing active safety by broadcasting emergency messages. In order to prevent broadcast storm of flooding-based broadcasting scheme in which any node receiving message will rebroadcast, the existing protocols use the different methods to limit the number of relay nodes. Nevertheless, the existing protocols have low delivery ratio with high traffic density and cause message overhead. Currently, the dramatic increase in the number of vehicles equipped with Global Positioning System (GPS) and onboard radar created new application scenarios that were not feasible before. Consequently, we proposed a broadcasting protocol that selects relay node by using GPS-based position information and detecting neighboring vehicles with the help of onboard radar to. Simulation results show that our proposed protocol has better performance than the existing schemes.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.2
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• pp.1-11
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• 2010

The provision of warning information on upcoming hazards leading to potential crash occurrence is a significant countermeasure to prevent crashes on the highway. This study presents a methodology for selecting more effective warning messages using a multi-criteria value function. The understandability, preference level, and message reading time were used as measures of effectiveness (MOE) for messages. Expert judgements were incorporated into the value function by analytical hierarchical process (AHP) technique. Field experiments to evaluate the warning messages were conducted in a testbed section on the Jungboo-Naeryuk freeway. The proposed methodology would be a useful tool to support the design of various traffic information messages.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.295-302
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• 2016

Many countries, especially ICT powers, are supporting IoT-based technology at a national level and this technology is actively being researched in the businesses and research institutes in an aim to develop technology and create an ecosystem. Roads in the Seoul city are building public facilities based on IoT to provide various services and conveniences for the users. However, for the full-fledged introduction and development of IoT, there are many cases where infringement on security and privacy and threat for life and safety happen. Also, as the IoT environment includes various environment technologies such as the existing sensor network, heterogeneous communication network, and devices optimized for the IoT environment, it inherits the existing security threat and various attack techniques. This paper researches the attribute based encryption technology for safe communication in the IoT environment. The data collected from the device is transmitted utilizing the attribute based encryption and by designing the key generation protocol, grades and authorities for the device and users are identified to transmit safe messages.

• Journal of Computing Science and Engineering
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• v.1 no.1
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• pp.56-73
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• 2007

Demands have been growing in safety-critical application fields for producing networked real-time embedded computing (NREC) systems together with acceptable assurances of tight service time bounds (STBs). Here a service time can be defined as the amount of time that the NREC system could take in accepting a request, executing an appropriate service method, and returning a valid result. Enabling systematic composition of large-scale NREC systems with STB certifications has been recognized as a highly desirable goal by the research community for many years. An appealing approach for pursuing such a goal is to establish a hard-real-time (HRT) component model that contains its own STB as an integral part. The TMO (Time-Triggered Message-Triggered Object) programming scheme is one HRT distributed computing (DC) component model established by the first co-author and his collaborators over the past 15 years. The TMO programming scheme has been intended to be an advanced high-level RT DC programming scheme that enables development of NREC systems and validation of tight STBs of such systems with efforts far smaller than those required when any existing lower-level RT DC programming scheme is used. An additional goal is to enable maximum exploitation of concurrency without damaging any major structuring and execution approaches adopted for meeting the first two goals. A number of previously untried program structuring approaches and execution rules were adopted from the early development stage of the TMO scheme. This paper presents new concrete justifications for those approaches and rules, and also discusses new extensions of the TMO scheme intended to enable further exploitation of concurrency in NREC system design and programming.