• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.443-447
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• 2010

본 연구에서는 우리나라의 소 중 대형 산불의 공중진화 방화선 구축형태에 대하여 제안하였다. 산불확산은 현장의 지세, 경사, 바람, 수종 등에 영향을 받으므로 공중진화 방화선을 구축할 때에는 연소방향 및 형태, 강도 등을 분석한 후 진화작업을 실시하여야 하며, 공중진화 방화선 형태를 A형에서 M형까지 13개로 제안하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.754-756
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• 2004

본 논문에서는 칸투어 추적의 정확도 향상을 위하여 배경이 제거된 에지 중에서 실제로 추적하고자 하는 객체의 경계선에 존재하는 에지들을 선택하는 방법을 제안한다 우리는 전 프레임에 존재하는 객체 칸투어의 수직 방향 그래디언트를 계산한다. 또한 다양한 크기를 가진 면적의 개념을 사용한 그래디언트 계산은 노이즈에 의한 영향이나 작은 체크무늬의 텍스쳐를 가진 장면에서도 정확하게 객체의 경계선에 존재하는 에지를 선택할 수 있게 한다. 우리는 이렇게 다양한 크기로 계산된 그래디언트값들은 가중치를 사용하여 합으로 계산하고 이 값이 큰 에지들을 경계선에 존재하는 에지로 고려한다.

• Review of KIISC
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• v.33 no.6
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• pp.51-54
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• 2023

국제해사기구(IMO)는 2017년 해사안전위원회(Maritime Safety Committee, MSC)에서 안전관리시스템으로의 해상 사이버 리스크 관리 결의하였다. 또한 국제선급협회(IACS)는 선박 사이버 사고가 인명, 재산 및 환경에 심각한 영향을 미칠 수 있음을 인식하여, 사이버 이슈를 체계적으로 논의하기 위한 사이버시스템 패널을 2016년 신설하였다. IACS 는 2022년 4월, 신조선 사이버보안 통합 요구사항(UR E26) 및 기자재 시스템 사이버보안 통합 요구사항(UR E27)을 배포하였다. 이 규정은 2024년 건조 계약을 체결한 신조선에 강제 적용될 예정이다. 본 논문에서는 신조선에 대한 리스크 기반 사이버 설계보안 접근 방식을 제안한다.

• Journal of the Korean Society for Railway
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• v.17 no.1
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• pp.7-13
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• 2014

Stiffness variations and wave propagation/reflection in railway catenaries are the primary sources of contact loss between a pantograph and a railway contact wire. This paper analyzes which design parameter is more important for 200km/h conventional rail and 300km/h high-speed rail, in order to effectively reduce the contact loss. For the high-speed rail, the wave propagation and reflection in the overhead contact lines are more influential than the stiffness variation over a span. When the high-speed rail needs to speed-up, it is necessary to develop higher strength contact wires in order to increase the wave propagation speed. In addition, the dropper clamp mass should be reduced in order to alleviate the wave reflection. However, it is noted that the increase in the tension to a messenger wire could deteriorate the current collection quality, which contrasts with expectations. For the 200km/h conventional rail, the stiffness variation over a span is more influential than the wave propagation and reflection. Therefore, shortening span length, increasing the tension in the contact wire and optimizing the location of the droppers are recommended for a smoother stiffness variation over the span.

• Korean journal of applied entomology
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• v.33 no.4
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• pp.263-269
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• 1994

A method to control the cigarette beetle. Losioderma serricorne F, m cigarettes by using gamma ray irradiation was evaluated When all stages of cigarette beetle were placed in gelatin capsules and irradiated wlth gamma ray. no eggs survived, but mortalities of pupae, larvae and adults exposed to above 0.8 kGy of gamma ray were only from 0 to 30%. Similar results were also obtained in the control efficacy of the beetle when seuqal kinds ot currently produced ngarettes containing m gelatin capsules were inadhated with gamma ray The cigarette beetle adults and larvae surviving gamma ray inadiatlon were reared on artificial d~etsto show that there were no reproduc. tions was observed in the second generation. The survival periods for each growth stage became shoter with increase gamma ray dosage. The fouirh instar larvae had the longest sulvlvai periods No sign~ficant changes of cigarette flavor and taste were noticed alter gamma ray inadiation. The cigarette packet, metal fotl for packet and cigarette paper by the inad~atlon were not discolored by irradiation.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.165-172
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• 1986

In electron therapy, lead cutout or low-melting alloy block is used for shaping the field. Material for shaping electron field affects the output factor as wet 1 as the collimation system. The authors measured the output factors of electron beams for shaped fields from Clinac-18 using ionization chamber of Farmer type in polystyrene phantom. They analyzed the parameters that affect the output factors. The output factors of electron beams depend on the incident energy, collimation system and size of shaped field. For shaped field the variation of output factor for the field size (A/P) has appearence of a smooth curve for all energy and all applicator collimator combination. The output factors for open field deviate from the curves for shaped fields. An output factor for a given field can be calculated by equivalent field method such as A/P method, if a combination of applicator and collimator is fixed.

• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.345-353
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• 2021

Digital radiography imaging systems can also help diagnose lesions in patients, but if x-rays that enter the human body cause scatter x-ray due to interaction with substances, they affect the signal and noise characteristics of digital x-ray images. To regard the human body as polymethyl methacrylate (PMMA) and observe the properties of scattered x-ray generated from PMMA on x-ray images, we analyze signal and noise in the spatial domain as well as noise-power spectrum (NPS), and detective quantum efficiency (DQE) at zero frequency. As PMMA thickness increased, signals decreased, the noise increased, and NPS degradation was identified in overall spatial frequencies. Based on these characteristics, zero-frequency performance was also shown to be degraded. Comparative analysis with Monte-carlo simulations will need to be made to analyze the zero-frequency performance by scattered x-ray of indirect conversion-type x-ray detectors more quantitatively.

• Therapeutic Science for Rehabilitation
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• v.7 no.4
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• pp.57-66
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• 2018

Objective: The purpose of this study is to investigate the effect of interactive metronome (IM) training on attention among children on the autistic spectrum. Methods: This is a single case study, using ABA design, of one child with autism spectrum disorder (ASD) who had attentional difficulties. A total of 20 sessions were conducted: 3 baseline sessions (A), 14 intervention sessions (B), and 3 follow-up baseline sessions (A'). During the intervention period (B), IM training was performed. Inattention and attention activities were measured as the dependent variables in all three phases (A, B, and A'). Results: Compared to baseline, the subject's inattention decreased in the IM training mediation period, and the performance of activities requiring attention also improved. The intervention effect was maintained even during the follow-up baseline period. Conclusion: The results of this study suggest that IM training positively influences attention among children with ASD with attention deficit symptoms. Further, it provides the clinical basis of IM training as an intervention for children with ASD.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.111-115
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• 2014

Power line communications can be utilized to build up the data transmission network wherever the electricity is available. This type of communication system could provide a basis for the network construction in many application areas which include the smart grid and home networks. On the other hand the power line communication is vulnerable to various types of interferences and noises. Also, its channel characteristics are constantly changing depending on the type and the amount of electrical loads connected to the network. Especially, the usage of DC power supply has been increased due to the explosive expansion of smart devices in our daily lives which result in the increased level of interferences on the power line channel. In this paper, the effect of the operation of the DC power supplies on the channel characteristics and the data transmission performance is analyzed through the experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.2
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• pp.218-230
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• 1993

A power line modem(PLM) which transfers data safely through power lines in houses or small offices is considered. When a power line is used for communications, transmitted signals could be affected by the channel characteristics such as frequency-selective fading, interference, and time-varying attenuation. In order to overcome these impairments, a direct sequence(DS) technique which is well known as an effective instrument against a variety of interferences and hostile channel properties is employed. Using a DS technique, however, requires more circuits such as PN code generator circuits, code modification circuits, and complicated synchronization circuits, and it also results in substantial acquisition delay. In this paper, some of these circuits are implemented via software programmed in the system controller, and the complicated synchronization circuits are replaced by simple circuits utilizing a 60 Hz power signal for synchronization. The synchronization ciruits used in this paper virtually eliminate the substantial acquisition delay, and is also designed to free influence of 60 Hz zero crossing jitters which reside in a power signal. As a result, a PLM using a DS technique is realized in the form of wall-socket plug, and the PLM hardware would be very much simplified.