• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.20-30
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• 2017

Due to the evolution of wireless communications technology, Long Term Evolution (LTE), which is a $4^{th}$ generation mobile communications system, has been adopted as a railway communications system. This LTE Railway (LTE-R) system is composed of various elemental functions, which are largely categorized into public safety and wireless communications for train control. Research on the public safety functions of railway communications have their roots in TRS based national public safety communication systems, and research on wireless communications functions for train control have their roots GSM-R, which is utilized by the ETCS in Europe. Based on these circumstances, this paper first analyzes the requirements for developing public safety technology in LTE-R, and compares those requirements with the functions of public safety LTE (PS-LTE), which is being deployed for the first time in the world by the South Korean government. Based on an analysis of the common and specific functions of LTE-R and PS-LTE, we conclude that there is little problem in integrating LTE-R and PS-LTE from the perspective of functionality. Second, this paper provides a comparison of the LTE-R requirements for the Quality of Service (QoS) with those of GSM-R utilized by the ETCS. This offers a guideline to allow LTE-R to be applied to a 500km/h train control system.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.9-15
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• 2017

In this paper, we propose a resource allocation scheme for high-power user equipment (HPUE) in public safety communication environments. The use of HPUE is being considered to increase the throughput and communication range of a UE in the disaster area where normal communication links are not available. However, HPUE may cause higher interference to UE's in adjacent cells that are allocated to the same radio resources. Therefore, it is necessary to deal with the potential interference through frequency planning and resource allocation. The performance of the proposed resource allocation scheme is evaluated through simulations in 3GPP public safety communication scenarios.

• Journal of the Korea Society of Computer and Information
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• v.21 no.2
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• pp.43-49
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• 2016

In this paper, we propose the controllability function and service design to efficiently implement the control of the disaster communication network, using Internet of Things(IoT) Technology. In accordance with the spread of Information Communication Technology(ICT), the era for building a disaster communications system without exclusion over the entire areas has emerged. National wireless mesh networks for public safety and disaster relief have been evolving to strengthen the pre-disaster response system using the latest technologies through the convergence of various technologies and services from the viewpoint of the command and control between disaster response agencies. In line with such a technological paradigm shift, the controllability of the objects in the IoT has been emerging as a key quality requirement of a disaster communications system. In this study, the objects are classified by the subject of control according to the IoT component, such as data, network resources and services in order to effectively implement their controllability. In addition, based on the destination of this controllability, technologies and services have been designed that can reduce the damage caused by disasters. Technologies and services that were derived from this study must be implemented in the current disaster safety network systems together with the establishment of an infrastructure for the networks in order that all persons are able to effectively utilize the disaster communications system for their safety.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1481-1489
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• 2016

A art from the typical data services based on 1:1 data communications, various new services based on 1:N communications have recently appeared. These services are becoming to require advanced 1:N communication schemes which can transfer the same data to many receivers efficiently and in high-performance. Especially, a Push-To-Talk (PTT) service, which is an important service in public safety communication system, requires a service server to disseminate the same voice media data to multiple receivers in a group in real-time and low latency. In this paper, we propose an efficient scheme to disseminate the same data to multiple receivers in low latency. In addition, we provide an analysis which gives a guide the performance of the 1:N communications in practical wired/wireless system environments in the perspective of the PTT service index.

• Journal of IKEEE
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• v.23 no.1
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• pp.214-223
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• 2019

This paper presents methodologies and strategies for developing standard operating procedures (SOPs) that are essential for practical use of disaster communication systems. Therefore, the various factors related to the SOP of the public safety network(SafeNet) are identified and analyzed, and the processes and strategies for the effective development of the SOP are developed and presented based on the analysis. In addition, the proposed SOP is reflected in LTE, which is public safety network implementation technology, and suggests how priority and QoS that are the basis of radio resource allocation should be operated.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.327-335
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• 2015

Wireless mesh networks for public safety and disaster have been developing in a direction from TETRA(TErrestrial Trunked RAdio) to take advantage of the Public Safety-LTE(Long Term Evolution) technology. In Korea, the Disaster Safety Network Building Project has been promoted in order to unify disaster communication systems among disaster response agencies. In this study, the trends of the network construction for national disaster communication and corresponding representative cases of overseas have been analyzed. Through this process, the disaster communication area in line with the purpose of communications. As a result, the disaster communication can be divided into five distinctive areas: the control, the response, the on-site, the victim and the alarm communications. Based on the re-designed communication areas, quality requirements have also been re-organized in this study. Ultimately the construction method for the Disaster Communication systems without exclusion zone will be presented.

• Safety and Health at Work
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• v.12 no.3
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• pp.365-369
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• 2021

Background: Law enforcement communications (i.e., 911 dispatch and call takers) is a challenging and stressful occupation. The purpose of this study is to identify the main stressors associated with employment in law enforcement communications, and to identify and provide context to how these stressors affect workers' health and wellbeing. Methods: This research study included focus groups with 23 call takers and 911 dispatchers employed by a large, urban law enforcement agency in 2018. Thematic analyses were conducted to identify trends. Results: Four themes of stressors emerged (i.e., the high stakes nature of some 911 calls for service, understaffing, supervisor-related stress, and recruiting practice). Two health-related themes emerged as being occupation-related: weight gain and poor sleep patterns/insufficient sleep). Specifically, participants reported negative eating habits resulting in weight gain and obesity, lack of sleep and irregular sleep schedules, and development of hypertension and/or diabetes since beginning their jobs. Conclusion: Law enforcement communications professionals experience a number of the same stressors facing law enforcement officers in patrol. These stressors, combined with the sedentary nature of the job, could result in long-term, chronic health problems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1440-1442
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• 2016

As long term evolution (LTE) is the most widely deployed broadband communication technology so far, efforts are being made to develop LTE-based mission critical public safety (PS) communication systems. In this paper, we propose a device-to-device (D2D) discovery-based radio resource acquisition scheme to support the LTE D2D communication to PS systems and the realization of resource forwarding for user equipments in emergency area.

• Korean System Dynamics Review
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• v.15 no.1
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• pp.51-74
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• 2014

Despite the high efficiency of nuclear power plant, people in Korea do not give approvals and supports the facilities because the risk of the accidents and incidents. In particular, the low level of safety culture is a crucial mechanism that damages the robustness of the NPP. By considering the various definitions of safety culture and analyzing the major reasons of incidents, the conceptual safety culture model is made by using Causal Loop Diagramming. For sustaining development of nuclear power, social supports, incentives and organizational learning are needed. It also requires the coordination of work schedules and the expansion of human resource for protecting the rules and procedures in NPP. Decommissioning aging nuclear power plants will prevent a serious accident. In order to promote the safety culture, Korea Hydro & Nuclear Power Corporation should disclose more information to the public and promote the internal and external communications.

• Journal of Digital Contents Society
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• v.16 no.1
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• pp.43-51
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• 2015

South Korea decided to use the public safety long term evolution (PS-LTE) method to build a wireless communications network for national disaster. The move will allow all disaster management agencies, including police, firefighters and the military to use multimedia information, including videos, in addition to voice to carry out rescue operations from 2017. The Ministry of Science, ICT and Future Planning said Thursday that it adopted PS-LTE as the technology method for national disaster management system following a national policy coordination meeting last month. PS-LTE is a method integrating group communication, direction communication between terminals and independent base station function with existing LTE technology. Until now, disaster management agencies used technology that only allowed voice communication. However, transmission of multimedia information is possible using PS-LTE.