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Location Optimization in Heterogeneous Sensor Network Configuration for Security Monitoring (보안 모니터링을 위한 이종 센서 네트워크 구성에서 입지 최적화 접근)

  • Kim, Kam-Young
    • Journal of the Korean Geographical Society
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    • v.43 no.2
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    • pp.220-234
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    • 2008
  • In many security monitoring contexts, the performance or efficiency of surveillance sensors/networks based on a single sensor type may be limited by environmental conditions, like illumination change. It is well known that different modes of sensors can be complementary, compensating for failures or limitations of individual sensor types. From a location analysis and modeling perspective, a challenge is how to locate different modes of sensors to support security monitoring. A coverage-based optimization model is proposed as a way to simultaneously site k different sensor types. This model considers common coverage among different sensor types as well as overlapping coverage for individual sensor types. The developed model is used to site sensors in an urban area. Computational results show that common and overlapping coverage can be modeled simultaneously, and a rich set of solutions exists reflecting the tradeoff between common and overlapping coverage.

Ultimate strength performance of tankers associated with industry corrosion addition practices

  • Kim, Do Kyun;Kim, Han Byul;Zhang, Xiaoming;Li, Chen Guang;Paik, Jeom Kee
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.3
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    • pp.507-528
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    • 2014
  • In the ship and offshore structure design, age-related problems such as corrosion damage, local denting, and fatigue damage are important factors to be considered in building a reliable structure as they have a significant influence on the residual structural capacity. In shipping, corrosion addition methods are widely adopted in structural design to prevent structural capacity degradation. The present study focuses on the historical trend of corrosion addition rules for ship structural design and investigates their effects on the ultimate strength performance such as hull girder and stiffened panel of double hull oil tankers. Three types of rules based on corrosion addition models, namely historic corrosion rules (pre-CSR), Common Structural Rules (CSR), and harmonised Common Structural Rules (CSR-H) are considered and compared with two other corrosion models namely UGS model, suggested by the Union of Greek Shipowners (UGS), and Time-Dependent Corrosion Wastage Model (TDCWM). To identify the general trend in the effects of corrosion damage on the ultimate longitudinal strength performance, the corrosion addition rules are applied to four representative sizes of double hull oil tankers namely Panamax, Aframax, Suezmax, and VLCC. The results are helpful in understanding the trend of corrosion additions for tanker structures.

Method for High-Frequency Modeling of Common-Mode Choke (공통모드 초크의 간단한 고주파 모델링 기법)

  • Jung, Hyeonjong;Yoon, Seok;Kim, Yuseon;Bae, Seok;Lim, Yeongseog
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.12
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    • pp.964-973
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    • 2017
  • In this paper, we analyze the effects of parasitic components of common-mode choke on the common mode and differential mode in a wide band, and we propose a simple method for high-frequency modeling. Common mode and differential mode 2-port networks were configured and the S-parameters in each mode were measured using a network analyzer. Equivalent circuit elements were extracted from the measured results to model a high-frequency equivalent circuit, and the validity was verified by comparing the measured S-parameters with the simulation results.

Hydraulic Modal Analysis of High-Pressure Common-rail Fuel Injection System for Passenger Vehicle (승용 CR 연료분사시스템에 대한 유압 Modal 분석)

  • Sung, Gisu;Kim, Sangmyeong;Kim, Jinsu;Lee, Jinwook
    • Journal of ILASS-Korea
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    • v.20 no.1
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    • pp.14-19
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    • 2015
  • Recently, R&D demand for environmental friendly vehicle has rapidly increased due to its global environmental issues such as global warming, energy and economic crisis. Under this situation, the most realistic alternative way for environmental friendly vehicle is a clean diesel vehicle. The common-rail fuel injection system, as key technology of clean diesel vehicle, consists of a high pressure pump, common-rail, high pressure fuel line and electronic control injector. In common-rail high-pressure fuel injection system, high pressure wave of injection system and geometry of injector elements have a major effects on high-pressure fuel spray. Therefore, in this study, the numerical model was developed for analysis about the common-rail fuel pressure pulsation by using AMESim code. We could secure stability of common-rail high-pressure fuel injection system through optimal design of fuel line.

A Study on the Security System of the Web Based Defense Information Service Network (WEB 환경에서 국방정보통신망 정보보호체계 구축에 관한 연구)

  • 신유찬;남길현
    • Journal of the military operations research society of Korea
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    • v.28 no.1
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    • pp.115-135
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    • 2002
  • The limits of current DN(Defense networks), private and closed network, become to reality; for Example, high expense of construction and maintenance of networks, restriction of new subscribers on DN. Therefore, a network using web environment that reflect fast development of If and IS(Information Security) technology is demanded for MND. Meeting the requirement of reliable IS system and extension and improvement of DN using common network, we can reduce the expense to extend, maintain, repair DN, form the environment that makes military business cooperate better with civil company and government agency, advance implementing Defense computing and networking service for field small size units that was a exception of Defense digitalization. But it is essential to construct DN based on common network that there are security requisites; confidentiality, integrity, availability, efficiency, log, backup, restoration, that have to be realized at demanding level for IS. This thesis suggested four measurements; replacement DN with common network to resolve the requirements of building new network and improvement of performance for private DN, linkage with common network for new requirement, distribution of traffic using common network, configuration of DN using Internet and Proposed a refinement of IS management organization to treat security threat of common network flexibly, and LAN IS standard model of DN based on the web environment.

Improvement of inspection system for common crossings by track side monitoring and prognostics

  • Sysyn, Mykola;Nabochenko, Olga;Kovalchuk, Vitalii;Gruen, Dimitri;Pentsak, Andriy
    • Structural Monitoring and Maintenance
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    • v.6 no.3
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    • pp.219-235
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    • 2019
  • Scheduled inspections of common crossings are one of the main cost drivers of railway maintenance. Prognostics and health management (PHM) approach and modern monitoring means offer many possibilities in the optimization of inspections and maintenance. The present paper deals with data driven prognosis of the common crossing remaining useful life (RUL) that is based on an inertial monitoring system. The problem of scheduled inspections system for common crossings is outlined and analysed. The proposed analysis of inertial signals with the maximal overlap discrete wavelet packet transform (MODWPT) and Shannon entropy (SE) estimates enable to extract the spectral features. The relevant features for the acceleration components are selected with application of Lasso (Least absolute shrinkage and selection operator) regularization. The features are fused with time domain information about the longitudinal position of wheels impact and train velocities by multivariate regression. The fused structural health (SH) indicator has a significant correlation to the lifetime of crossing. The RUL prognosis is performed on the linear degradation stochastic model with recursive Bayesian update. Prognosis testing metrics show the promising results for common crossing inspection scheduling improvement.

Developing Accident Models of Rotary by Accident Occurrence Location (로터리 사고발생 위치별 사고모형 개발)

  • Na, Hee;Park, Byung-Ho
    • International Journal of Highway Engineering
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    • v.14 no.4
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    • pp.83-91
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    • 2012
  • PURPOSES : This study deals with Rotary by Accident Occurrence Location. The purpose of this study is to develop the accident models of rotary by location. METHODS : In pursuing the above, this study gives particular attentions to developing the appropriate models using multiple linear, Poisson and negative binomial regression models and statistical analysis tools. RESULTS : First, four multiple linear regression models which are statistically significant(their R2 values are 0.781, 0.300, 0.784 and 0.644 respectively) are developed, and four Poisson regression models which are statistically significant(their ρ2 values are 0.407, 0.306, 0.378 and 0.366 respectively) are developed. Second, the test results of fitness using RMSE, %RMSE, MPB and MAD show that Poisson regression model in the case of circulatory roadway, pedestrian crossing and others and multiple linear regression model in the case of entry/exit sections are appropriate to the given data. Finally, the common variable that affects to the accident is adopted to be traffic volume. CONCLUSIONS : 8 models which are all statistically significant are developed, and the common and specific variables that are related to the models are derived.

Parallel Model Feature Extraction to Improve Performance of a BCI System (BCI 시스템의 성능 개선을 위한 병렬 모델 특징 추출)

  • Chum, Pharino;Park, Seung-Min;Sim, Kwee-Bo
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.11
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    • pp.1022-1028
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    • 2013
  • It is well knowns that based on the CSP (Common Spatial Pattern) algorithm, the linear projection of an EEG (Electroencephalography) signal can be made to spaces that optimize the discriminant between two patterns. Sharing disadvantages from linear time invariant systems, CSP suffers from the non-stationary nature of EEGs causing the performance of the classification in a BCI (Brain-Computer Interface) system to drop significantly when comparing the training data and test data. The author has suggested a simple idea based on the parallel model of CSP filters to improve the performance of BCI systems. The model was tested with a simple CSP algorithm (without any elaborate regularizing methods) and a perceptron learning algorithm as a classifier to determine the improvement of the system. The simulation showed that the parallel model could improve classification performance by over 10% compared to conventional CSP methods.

Bayesian demand model based seismic vulnerability assessment of a concrete girder bridge

  • Bayat, M.;Kia, M.;Soltangharaei, V.;Ahmadi, H.R.;Ziehl, P.
    • Advances in concrete construction
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    • v.9 no.4
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    • pp.337-343
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    • 2020
  • In the present study, by employing fragility analysis, the seismic vulnerability of a concrete girder bridge, one of the most common existing structural bridge systems, has been performed. To this end, drift demand model as a fundamental ingredient of any probabilistic decision-making analyses is initially developed in terms of the two most common intensity measures, i.e., PGA and Sa (T1). Developing a probabilistic demand model requires a reliable database that is established in this paper by performing incremental dynamic analysis (IDA) under a set of 20 ground motion records. Next, by employing Bayesian statistical inference drift demand models are developed based on pre-collapse data obtained from IDA. Then, the accuracy and reasonability of the developed models are investigated by plotting diagnosis graphs. This graphical analysis demonstrates probabilistic demand model developed in terms of PGA is more reliable. Afterward, fragility curves according to PGA based-demand model are developed.

Suggestion of the Characteristics of Element Technology and the Standard Model through the Comparison of Domestic Zero-energy Houses (국내 에너지제로하우스 비교를 통한 요소기술 특성 및 표준 모델 제시에 관한 연구)

  • Lee, Chung-Kook;Lee, Jeong-Cheol;Kim, Sang-Su;Suh, Seung-Jik
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.8 no.2
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    • pp.27-35
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    • 2012
  • Five zero energy house models developed in Korea for the purpose of the energy performance were compared and analyzed in the study. The standard passive house model applying common technology and efficient energy performance elements was proposed. Standard passive house 5 models have been developed commonly aiming at 100% energy saving, applying high-performance and high-efficiency exterior thermal insulation, using 3 low-e coated window system, and targeting average 0.65 ACH to enhance privacy. Energy recovery ventilators and dry and cold radiant heating floor has been partially applied. Eco-design techniques such as the awning device, heat insulating door, using natural light have been used. Solar and geothermal systems as the application of renewable energy technologies have been commonly applied. And fuel cells were applied to a partial model. The standard model based on common technical elements and average performance of each element and obtained from five model analysis has been proposed in the study.