• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.27 no.1
• /
• pp.62-68
• /
• 2023

An aerial relay system utilizing an unmanned aerial vehicle(UAV) or drone is addressed for event-driven operations such as temporary communication services for disaster affected area, military and first responder support. UAV relay system (URS) targets to provide a reliable communication service to a remote user equipment or an operator, therefore, a fast UAV placement to guarantee a minimum quality of service(QoS) is important when an operation is requested. Researches on UAV utilization in communication systems mostly target to derive the optimal position of UAV to maximize the performance, however, fast deployment of UAV is much more important than optimal placement under emergency situations. To this end, this paper derives the feasible area for UAV placement, investigates the effect of performance requirements on that area, and suggests UAV placement to certainly guarantee the performance requirements. Simulation results demonstrate that the feasible area derived in this paper matches that obtained by an exhaustive search.

• Proceedings of the IEEK Conference
• /
• 2004.08c
• /
• pp.552-557
• /
• 2004

Mobile Ad Hoc Network (MANET) is a network architecture, which has no backbone network and is deployed temporarily and rapidly in emergency or war without fixed mobile infrastructures. All communications between network entities are carried in ad-hoc networks over the wireless medium. Due to the radio communications being extremely vulnerable to propagation impairments, connectivity between network nodes is not guaranteed. Therefore, previously developed routing algorithms in wired networks cannot be used. And many new algorithms have been undergone. This study proposes the secondary leader approach to the cluster based routing protocol(CBRP). In case, the primary leader becomes abnormal status so that the primary leader cannot participate the communications between network entities, the secondary leader immediately replaces the primary header without selecting process of the new primary leader. The performances of proposed algorithm ACBRP(Advanced Cluster. Based Routing Protocol;CBRP using secondary leader) are compared with CBRP and results are presented in order to show the effectiveness of the algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.7
• /
• pp.1833-1841
• /
• 1996

Recently, by emerging of the ALE techniques that make it possible to providereliable communications link automatically, high frequency communiation is newly used as emergency communication and back-up for satellite communications. ALE signal is transmitted in burst, and the received signal is subject to distortions by detrimental multipath fading channels. In the case of that channel, the performance of ALE system is highly dependent upon that of synchronization techniques. In this paper, M-ary FSK signals are detected by a bank of bandpass filter, which is implemented using recusive DFT(Discrete Fourier Transform). Also an acquisition and trancking algorithm are designed uisng parallel structure and early-late-gate methods respectively. Finally, we verify the performance ofthe proposed synchronization algorithm by the computer simulation.

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

• Nuclear Engineering and Technology
• /
• v.44 no.8
• /
• pp.897-910
• /
• 2012

Inappropriate communications can cause a lack of necessary information exchange between operators and lead to serious consequences in large process systems such as nuclear power plants (NPPs). In this regard, various kinds of taxonomies of inappropriate communications have been developed to prevent inappropriate communications. However, there seems to be difficult to identify inappropriate communications from verbal protocol data between operators. Because the existing taxonomies were developed for use in report analysis, there is a problem of 'uncertainty'. In consequence, this paper proposes a new taxonomy of inappropriate communications and provides some insights to prevent inappropriate communications. In order to develop the taxonomy, existing taxonomies for four industries from 1980 to 2010 were collected and a new taxonomy is developed based on the simplified one-way communication model. In addition, the ratio of inappropriate communications from 8 samples of audio-visual format verbal protocol data recorded during emergency training sessions by operating teams is compared with performance scores calculated based on the task analysis. As a result, inappropriate communications can be easily identified from the verbal protocol data using the suggested taxonomy, and teams with a higher ratio of inappropriate communications tend to have a lower performance score.

• Journal of Satellite, Information and Communications
• /
• v.7 no.3
• /
• pp.58-62
• /
• 2012

Emergency alerting broadcasting of T-DMB is being serviced to deliver the event of a disaster to the people quickly and effectively through a T-DMB network. DGPS has been developed in order to improve the accuracy of the GPS receiving data and transmitting of DGPS information through the T-DMB network is being studied for a wide range of usage. Because DGPS information and AEAS message are sent through the same T-DMB network, if DGPS information is applied to AEAS message disaster area can be specified more precisely and the exact location of the disaster can be measured in the terminal. In this paper, a implementation method of T-DMB emergency alerting broadcasting system based on a DGPS including a new structure of AEAS message was proposed to identify the location of disaster accurately.

• Journal of Advanced Navigation Technology
• /
• v.13 no.6
• /
• pp.950-956
• /
• 2009

Nowdays the mobile traffic have been greatly increasing. This traffic increment has been caused the lack of frequency. To solve this problem, many study to improve the frequency efficiency in the field of mobile communication has been performed in a variety angle. However this kind of study was focused to 1:1 traffic. This paper propose the allocation scheme of the receiving channel in 1:N group traffic. This method apply to the TRS(Trunk Radio System) that use for the emergency disaster telecommunications. The result of the study show the performance improvement in the call loss ratio and load distribution in the group channel.

• Journal of Communications and Networks
• /
• v.14 no.3
• /
• pp.230-236
• /
• 2012

Based on the known binary sequence sets and Gray mapping, a new method for constructing quaternary sequence sets is presented and the resulting sequence sets' properties are investigated. As three direct applications of the proposed method, when we choose the binary aperiodic, periodic, and Z-complementary sequence sets as the known binary sequence sets, the resultant quaternary sequence sets are the quaternary aperiodic, periodic, and Z-complementary sequence sets, respectively. In comparison with themethod proposed by Jang et al., the new method can cope with either both the aperiodic and periodic cases or both even and odd lengths of sub-sequences, whereas the former is only fit for the periodic case with even length of sub-sequences. As a consequence, by both our and Jang et al.'s methods, an arbitrary binary aperiodic, periodic, or Z-complementary sequence set can be transformed into a quaternary one no matter its length of sub-sequences is odd or even. Finally, a table on the existing quaternary periodic complementary sequence sets is given as well.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.5
• /
• pp.9-15
• /
• 2013

In this paper, automatic recognition of an accident and whether service delivery and risk driving through the giving of the driver to correct driving habits before and after the accident to reproduce highly scalable video Smart Mobile Blackbox DVR (SMBD, Smart Mobile Blackbox DVR) Computer of the model was designed. SMBD on embedded systems equipped with wireless capabilities to sleep in the car accident point and the image information by wireless communications, by notification in the control center, 24-hour emergency rescue service and traffic information can be provided. The vehicle ECU (Electronic Control Unit) of the vehicle information and sensor data in conjunction with wireless eCall (Emergency Call) services can be realized.

• Journal of Korea Society of Industrial Information Systems
• /
• v.12 no.5
• /
• pp.60-70
• /
• 2007

As Republic of Korea community nears to old age society rapidly, various kinds problem about old mans is risen. Can speak that item connected with medical treatment is more serious in the importance aspect among them Therefore, many-sided effort is consisting to ready countermeasure in reply, but economical method is not presented clearly as being realistic yet. Also, medical treatment service that more users through diffusion of fast internet are little more better effort that serve consist. But, in the case of old age, by difficulty of the use, restriction condition happens. In this paper proposed system that is prevailing already and user-friendly can cope curtly in old mans' emergency situation more rapidly and conveniently using mobile phone of CDMA way relatively.