• Title/Summary/Keyword: Alarm setting

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A Study on Loading Arm Envelope and Alarm Setting according to Ship Movement

  • Choi, Byoung-Yeol;Jo, Hyo-Jae;Choi, Han-Sik;Choi, Dong-Eon
    • Journal of Advanced Research in Ocean Engineering
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    • v.4 no.3
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    • pp.115-123
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    • 2018
  • This study was carried using the new approach method to design appropriately the Loading Arm length and the alarm setting according to ship movements on Loading and Unloading marine Berth. The quasi-static mooring analysis was performed to estimate 110,000DWT ship's movements based on environmental conditions such as wind, current and wave. The mooring motion of the ship is very important to determine the loading arm scope, and in this case, the operation condition is performed on the ship without considering the damaged condition of the mooring line because the ship movement in case of damage is larger than intact, and all operations are stopped, the loading arm being released due to control system. From the result of mooring analysis, motion displacements, velocities and accelerations were simulated. They were used to simulate the maximum drifting speeds and distances. The maximum drifting speeds were checked to be satisfied within drifting speed limits. The total maximum drifting distances were simulated with alarm steps of the new approach method. Finally, the loading arm envelopes using the total maximum drifting distances were completed. Therefore, it was confirmed that the new approach method for loading arm envelopes and alarm settings was appropriate from the above results. In the future, it will be necessary to perform the further advanced dynamic mooring analysis instead of the quasi-static mooring analysis and to use the precise computer program analysis for various environments and ship movement conditions.

Performance Analysis of Cooperative Spectrum Sensing Based on Sharing Threshold among cooperative users (협력 노드의 합리적 임계치 공유를 통한 센싱 검출 성능 분석)

  • Seo, SungIl;Lee, MiSun;Kim, Jinyoung
    • Journal of Satellite, Information and Communications
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    • v.8 no.1
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    • pp.66-70
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    • 2013
  • In this paper, Threshold setting method is proposed to improve detection probability for cooperative sensing. Even if cooperative users have all same false alarm rate, each user has different threshold due to pass ad-hoc channel. threshold level is related to detection probability. So, we select the highest threshold among cooperative users and then share threshold information for getting the high detection probability.

Performance Analysis of Spectrum Sensing using CSI with False Alarm Selection (채널상태정보에 따른 False alarm 선택 스펙트럼 센싱 성능 분석)

  • Lee, Mi Sun;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.8 no.4
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    • pp.1-5
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    • 2013
  • CR(Cognitive Radio) technology is maximized frequency reuse using unused frequency band. Conventional cooperative spectrum sensing has fixed false alarms. so all cooperative user has equal threshold. This problem is caused degradation of detection probability. so we propose and analysis the system model that false alarm differential setting through CSI(channel state information) for resonable threshold. Simulation results show improvement of detection probability.

A Rear Alarm System using Ultra-sonic Wave Sensor (초음파센서를 이용한 후방경보시스템)

  • Lee, Yeong-Roh;Lee, Jeung-Hyun;Park, Jeung-Soo;Kim, Tae-Hyun;Cho, Wan-Hee;Lee, Dong-Hyun;Soh, Dea-Wha
    • Journal of the Speleological Society of Korea
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    • no.79
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    • pp.47-51
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    • 2007
  • As time goes by, ultrasonic wave is getting important and new technology, which is adapted to ultrasonic wave is used to industry such as home appliance, automobile, and high-tech industry. Especially, ultrasonic wave is used an alarm device whether there are things at the rear of I. It's do important device in automobile system because it can prevent car-accident from inattention of the driver. Actually, there has already been lots of the alarm device. But it's expensive and so difficult to set the device. So almost driver don't set device at their automobile. We focus on these problems. We want to make cheap md easy setting device. Ultrasonic wave sensor emits Ultrasonic-signal at outgoing part and receive part accept the signal. Sensor analyzes the signal and Distance is displayed on LCD of device. The device makes alarm if distance is near from something of rear. The device makes break-system operate to prevent drivers from crashing if distance is so near. This device is portable. So normal deriver can set it easily.

A Study on the Development of Fire Alarm System with Evacuation Lighting and Voice Alarm Functions (피난조명 및 음성경보 기능을 내장한 화재경보시스템 개발에 관한 연구)

  • Lee, Gun-Ho;Choi, Su-Gil;Kim, Si-Kuk
    • Fire Science and Engineering
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    • v.32 no.4
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    • pp.25-34
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    • 2018
  • This study investigated the development of a fire alarm system with evacuation lighting and voice alarm functions. The performance of a fire detector and system with independently built-in evacuation lighting and voice alarm functions was confirmed for early recognition of fire and to allow visibility of the evacuation route in the event of fire. This new system satisfied model recognition and product testing technological standards with 1.62 lx average illumination, 89.7 dB average sound and 86.1 dB average voice. From additionally testing the evacuation performance of this new system, it was confirmed that the evacuation time decreased by 63.08% to 67.82% under the experimental conditions compared to conventional systems. The new system can minimize fire damage by setting off voice alarms to prevent failure of fire recognition and by flashing emergency lighting to secure the minimum required visibility range for evacuation. Therefore, it is considered that it will be utilized as a fire alarm system with appropriateness and usefulness by considering people with hearing or visual impairment.

The Surface Sidelobe Clutter and the False Alarm Probability of Target Detection for the HPRF Waveform of the Microwave Seeker (마이크로파 탐색기의 HPRF 파형에 대한 지표면 부엽클러터와 표적탐지 오류 확률)

  • Kim, Tae-Hyung;Yi, Jae-Woong;Byun, Young-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.4C
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    • pp.476-483
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    • 2009
  • Tracking and detecting targets by the microwave seeker is affected by the clutter reflecting from the earth's surface. In order to detect retreating targets in look-down scenario, which appear in the sidelobe clutter (SLC) region, in the microwave seeker of high pulse repetition frequency (HPRF) mode, it is necessary to understand statistical characteristics of the surface SLC. Statistical analysis of SLC has been conducted for several kinds of the surface using data obtained by the captive flight test of the microwave seeker in the HPRF mode. The probability density function (PDF) fitting is conducted for several kinds and conditions of the surface. PDFs and PDF parameters, which best describe statistical distribution of the SLC power, are estimated. By using the estimated PDFs and PDF parameters, analyses for setting the target-detection thresholds, which give a desired level of target-detection false alarm probability, are made. These analysis materials for statistical characteristics of SLC power and the target-detection threshold can be used in various fields, such as development of a target-detection method, the constant false alarm rate processing.

Reference Model Updating of Considering Disturbance Characteristics for Fault Diagnosis of Large-scale DC Bus Capacitors (대용량 직류버스 커패시터의 고장진단을 위한 외란특성 반영의 레퍼런스 모델 개선)

  • Lee, Tae-Bong
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.4
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    • pp.213-218
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    • 2017
  • The DC electrolytic capacitor for DC-link of power converter is widely used in various power electronic circuits and system application. Its functions include, DC Bus voltage stabilization, conduction of ripple current due to switching events, voltage smoothing, etc. Unfortunately, DC electrolytic capacitors are some of the weakest components in power electronics converters. Many papers have proposed different algorithms or diagnosis method to determinate the ESR and tan ${\delta}$ capacitance C for fault alarm system of the electrolytic capacitor. However, both ESR vary with frequency and temperature. Accurate knowledge of both parameters at the capacitors operating conditions is essential to achieve the best reference data of fault alarm. According to parameter analysis, the capacitance increases with temperature and the initial ESR decreases. Higher frequencies make the reference ESR with the initial ESRo value to decrease. Analysis results show that the proposed DC Bus electrolytic capacitor reference ESR model setting technique can be applied to advanced reference signal of capacitor diagnosis systems successfully.

An Improved Analytic Model for Power System Fault Diagnosis and its Optimal Solution Calculation

  • Wang, Shoupeng;Zhao, Dongmei
    • Journal of Electrical Engineering and Technology
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    • v.13 no.1
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    • pp.89-96
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    • 2018
  • When a fault occurs in a power system, the existing analytic models for the power system fault diagnosis could generate multiple solutions under the condition of one or more protective relays (PRs) and/or circuit breakers (CBs) malfunctioning, and/or an alarm or alarms of these PRs and/or CBs failing. Therefore, this paper presents an improved analytic model addressing the above problem. It takes into account the interaction between the uncertainty involved with PR operation and CB tripping and the uncertainty of the alarm reception, which makes the analytic model more reasonable. In addition, the existing analytic models apply the penalty function method to deal with constraints, which is influenced by the artificial setting of the penalty factor. In order to avoid the penalty factor's effects, this paper transforms constraints into an objective function, and then puts forward an improved immune clonal multi-objective optimization algorithm to solve the optimal solution. Finally, the cases of the power system fault diagnosis are served for demonstrating the feasibility and efficiency of the proposed model and method.

Signal Detection of Cognitive Radio System for 3G LTE Mobile Communication System (3G LTE 이동통신 시스템을 위한 무선인지 시스템의 신호검출)

  • Kim, Seung-Jong;Kim, Jin-Young
    • Journal of Satellite, Information and Communications
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    • v.5 no.1
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    • pp.27-31
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    • 2010
  • Recently, spectrum requirements are rapidly increasing in accordance with wireless communication development. For this reason, FCC(Federal communications commission) is considering cognitive radio system to increase spectral efficiency. In this paper, we present the performance analysis of signal detection by using RS(Reference signal) for LTE environments. Especially, we analyze the performance of detection probability in case of downlink LTE system. In the simulation, we generate OFDMA signal format which is specified in the LTE system. We assume additive white Gausssian noise channel environment. We estimate the performance by setting the threshold value of 5 % and 10 % based on CFAR(Constant false alarm rate) and false alarm rate, respectively. Finally, we discuss a future study plan on the applicability of CR to the LTE system.

A Study on Risk Analysis and Acident Prevention Heater Interlock By-pass (Heater interlock by-pass로 인한 위험분석 및 사고방지에 대한 연구)

  • Son Jae-geun;Park Kyo-Shik;Kang Tae-Yeon;Yeo Yeong-Koo
    • Journal of the Korean Institute of Gas
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    • v.7 no.1 s.18
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    • pp.24-27
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    • 2003
  • In this paper it was investigated 15 heaters of CDU plant heater, NCC plant heater, CO plant heater, Aromatic plant heater and so on while running in our country. It was also analysed the standard of operation procedure, the action in alarm, the interlock system, the operating situation of the interlock by-pass and major accident about the heater and so on. This paper presents the installation of the on-line monitoring, the additional installation of the local pressure gauge and temperature gauge, the check in starting operation,'the management of the interlock by-pass, the change of manufacturer causing the disorder of instrument sensor, the management method of DCS alarm for methods of the interlock prevention and facilities improvement. It was few information about the heater interlock in the inside and outside of the country We mainly have studied with reflecting the opinion of the operator and manager on site, the sheet of process trouble and operation procedure and so on. we think that the accident relating to the interlock will significantly reduce if the companies apply the conclusion of this study(i.e. methods of the interlock prevention and facilities improvement).

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