• Fire Science and Engineering
• /
• v.27 no.2
• /
• pp.89-96
• /
• 2013

In this research, the fire mistaken dispatch records for the past 11 years have been analyzed by using a statistic technique. Fire mistaken dispatch occurred yearly average $48,371{\pm}5,763$ time at 95 % confidence level. This is 1.2 times more than the dispatch for extinguishing the fire. Fire mistaken dispatch has been increased mainly by malfunctioning alarm among other various reasons and the reason of mistaken dispatch is different depending on the population of the region. In big cities, the burning smell accounts for the most of mistaken dispatch but in rural areas, the garbage incineration is the major reason for mistaken dispatch. As a result of calculating the mean time between fire mistaken dispatches (MTBFmd) by region, MTBFmd of Daejeon is 20.61 hr/time and its reliability is 95.26 % at t=1 hr. On the other hand, the MTBFmd of Gyeonggi is 0.58 hr/time and its reliability is 17.91 % at t=1 hr.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.5
• /
• pp.349-357
• /
• 2022

Since the flight control computer of unmanned aerial vehicle (UAV) is a flight critical equipment, it is necessary to ensure reliability and safety from the development step, and a redundancy-based fault management design is required in order to operate normally even a failure occurs. To reduce cost, weight and power consumption, the dual-redundant flight control system design is considered in UAV. However, there are various restrictions on the fault management design. In this paper, we propose the fault detection and isolation designs for the dual-redundant flight control computer to satisfy the safety requirements of an UAV. In addition, the flight control computer developed by applying the fault management design performed functional tests in the integrated test environment, and after performing FMET in the HILS, its reliability was verified through flight tests.

• International Journal of Internet, Broadcasting and Communication
• /
• v.13 no.4
• /
• pp.103-111
• /
• 2021

In modern society, digital lifestyles are spreading to minimize contact with people and to receive contactless information. The spread trend has established an unmanned distribution system in which transactions through contactless technologies such as kiosks and chatbots are activated in face-to-face transactions with sellers and consumers. In order to streamline logistics supply worldwide, digital new deal based joint logistics hubs, unmanned courier storage platforms, and fresh logistics based last mile services have been developed into unmanned logistics systems, focusing on the intelligent logistics system automation process. Unmanned courier storage system installed in urban areas and home to daily logistics where volume is concentrated are provided with fresh logistics services through cold chain and receiving freights in contactless environments. Development is also underway to minimize safety accidents caused by courier services, such as managing various information based on the integrated control system. This paper defines the concept of integrated operation for the development of a platform for contactless unmanned courier storage device developed into next-generation logistics system. In addition, we intend to develop systems engineering-based output for deriving safety requirements and specifications by identifying risk sources that may occur in the operational scenario. Therefore, the goal is to establish a foundation for safety and reliability between interfaces of logistics systems to be installed in apartment and subway station environments that want to provide unmanned logistics services to various consumers.

• Journal of the Korean Society of Safety
• /
• v.35 no.2
• /
• pp.100-110
• /
• 2020

Recently, the frequency of typhoon and torrential rain due to climate change is increasing. In addition, the upsurge in the complexity of urban sewer network and impervious surfaces area aggravates the inland flooding damage. In response to these worsening situations, the central and local governments are conducting R&D tasks related to predict and mitigate the flood risk. Researches on the analysis of inundation in urban areas have been implemented through various ways, and the common features were to evaluate the accuracy and justification of the model by comparing the model results with the actual inundation data. However, the evaluation procesure using available urban flooding data are not consistent, and if there are no quantitative urban inundation data, verification has to be performed by using press releases, public complaints, or photos of inundation occurring through 'CCTV'. Because theses materials are not quantitative, there is a problem of low reliability. Therefore, this study intends to develop a comparative analysis procedure on the quantitative degree and applicability of the verifiable inundation data, and a systematic framework for the performance assessment of urban flood analysis model was proposed. This would contribute to the standardization of the evaluation and verification procedure for urban flooding modelling.

• International Journal of Safety
• /
• v.11 no.2
• /
• pp.15-21
• /
• 2012

This paper is aimed to develop an electrical fire detection system (EFDS) which can analyze the possibility of electrical fire for overcurrent, leakage current and arc signals of panel board in traditional market shop. The EFDS adopted fuzzy logic and precursory data for overcurrent, leakage current and arc signals to evaluate the possibility of electrical fire. The signals are obtained directly from panel board in traditional market shops and fuzzy membership function is obtained from experiment, simulation, expert's advice. The overcurrent data is acquired by thermal data of normal and abnormal states (partial disconnection) on the insulated electrical wire, in accordance with the increase of the current signal, The leakage current data is obtained under various environments. The arc signal is acquisited by waveforms of instantaneous value in time domain and frequency band in frequency domain. The Fuzzy algorithm for DB of EFDS consists of fuzzification, inference engine by Mamdani's method and defuzzification by center of gravity method. In order to verify the performance and reliability of EFDS, it was applied to Jeon-Ju traditional market shops (90 shops) in Korea. Results show that EFDS in this paper is useful in alarming the fire case, which will prevent severe damage to human beings and properties, and reduce the electrical fires in a vulnerable area of electrical disaster.

• Journal of Navigation and Port Research
• /
• v.40 no.1
• /
• pp.21-26
• /
• 2016

Even in the marine industry was required the looser positioning performance as compared to other application domain, a high-quality positioning performance and reliability are becoming ever more important. The high-quality performance includes not only accuracy but also integrity, continuity, and availability. However, current DGPS service is not satisfying the minimum positioning performance requirements for maritime user proposed by IMO. Especially, no one can guarantee the required integrity performance by DGPS service. This paper presents the advanced monitoring concept to strengthen the performance of current DGPS through the enhanced monitoring, guarantee and notice functions. To this, the limitations of the integrity monitoring function of current DGPS are analyzed, and a countermeasure is prepared to improve the limitations of the current integrity monitoring function. This paper can be applied as basis research to improvement of the DGPS service.

• Journal of the Society of Disaster Information
• /
• v.18 no.4
• /
• pp.754-768
• /
• 2022

Purpose: The purpose of this study is to derive improvements through user satisfaction analysis for the smart traffic safety system being applied to improve traffic safety. Method: A survey-based IPA analysis was used to derive system and service improvements for groups of drivers and pedestrians. Result: As a result of the analysis, both drivers and pedestrian groups showed that Quadrant 1(Keep up the Good Work) was 'Perception of risk information', and Quadrant 3(Low Priority) was 'Reliability of warning information'. On the other hand, 'AI display suitability', which was analyzed as Quadrant 1(Keep up the Good Work) in the driver group, was found to be Quadrant 3(Low priority) in the pedestrian group. Conclusion: Satisfaction factors for smart pedestrian safety systems may vary depending on users, and it is judged that user-centered system construction and service provision are necessary.

• The Journal of the Korea Contents Association
• /
• v.10 no.1
• /
• pp.426-435
• /
• 2010

The object of this study was to develop an index of service quality of waterparks and verify the validity and reliability of the index. This study represents the waterparks user population in 2009, and 250 people were extracted by using the purposive sampling method. In other words, five locations have major waterparks were chosen and 50 people per each location were collected. Conference, panel survey, exploratory factor analysis and confirmatory factor analysis were performed to verify the validity of the questionnaire while item analysis, interrater reliability and internal consistency reliability were conducted to probate the reliability. Through these methods and procedures, the results of this study like these; (i) Validity of this index was significantly high and the index include amenity/cleanness, safety, price, programs, facilities, accessibility and promotion. Among them, amenity/cleanness was the major factor for the validity value; (ii) Reliability of this index was also high. There are high correlations between questions and fields and questions and total score. And the Cronbach's $\alpha$ values of the internal consistency reliability was over 0.603 except in the case of promotion which was below 0.6. After all the analysis, the index of service quality proved to be very proper and reliable index. Therefore, the major factors of service quality have to be figured out and reflected to the management innovation to improve service quality of waterparks.

• Journal of KIISE
• /
• v.44 no.6
• /
• pp.559-565
• /
• 2017

A UAV(unmanned aerial vehicle) requires higher reliability for external effects such as electromagnetic interference because a UAV is operated by pre-designed programs that are not under human control. The design of a small UAV with a complete resistance against the external effects, however, is difficult because of its weight and size limitation. In this circumstance, a conventional small UAV dropped to the ground when an external effect caused the rebooting of the flight-control computer(FCC); therefore, this paper presents a novel algorithm for the improvement of the flight safety of a small UAV. The proposed algorithm consists of three steps. The first step comprises the calibration of the navigation equipment and validation of the calibrated data. The second step is the storage of the calibration data from the UAV take-off. The third step is the restoration of the calibration data when the UAV is in flight and FCC has been rebooted. The experiment results show that the flight-control system can be safely operated upon the rebooting of the FCC.

• Journal of Korea Water Resources Association
• /
• v.49 no.5
• /
• pp.381-389
• /
• 2016

In this study, we developed evaluation indicators of dam rehabilitation considering climate change in order to prepare for safety of aging dam facilities in accordance with changes in rainfall intensity. The validity and appropriateness of each indicator, and the evaluation criteria were selected for quantitative indicators for each detail through domestic and international case studies, literature review, and expert advice. The survey was carried out to estimate the importance of each indicator for dam rehabilitation. The subjective assessment of the respondents was rearranged using pairwise comparison from the Analytic Hierarchy Process (AHP). The reliability of the survey results was evaluated through consistent verification. In addition, a comparative assessment was carried out which evaluated the reliability importance estimation result to refine the criteria to distinguish rating scales between expert and non-expert groups on dam-related fields.